diff --git a/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/[product_id]/route.ts b/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/[product_id]/route.ts
index 955676687..d8ebbdee5 100644
--- a/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/[product_id]/route.ts
+++ b/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/[product_id]/route.ts
@@ -116,10 +116,9 @@ export const DELETE = createSmartRouteHandler({
         s.productId === params.product_id && isActiveSubscription(s)
       );
       if (subscriptions.length === 0) {
-        // Owned but with no active sub: either it's already winding down
-        // (canceled with a future endedAt — still in effect, not
-        // re-cancelable), or the customer owns it via OTP. Distinguish the
-        // two so a double-cancel doesn't claim the product is an OTP.
+        // Owned but no active sub: either already winding down (canceled
+        // with a future endedAt) or owned via OTP — don't claim the former
+        // is a one-time purchase.
         const nowMillis = Date.now();
         const windingDown = allSubs.find(s =>
           s.productId === params.product_id && isSubscriptionInEffect(s, nowMillis)
@@ -136,12 +135,9 @@ export const DELETE = createSmartRouteHandler({
     for (const subscription of subscriptions) {
       if (subscription.stripeSubscriptionId) {
         const stripeClient = stripe ?? throwErr(500, "Stripe client missing for subscription cancellation.");
-        // Cancel at period end (not `subscriptions.cancel()`, which ends the
-        // sub immediately) — the confirm dialog promises the customer keeps
-        // what they paid for until the period ends, and the local-sub branch
-        // below implements the same semantics via a future `endedAt`. The
-        // Stripe webhook syncs the local row (and flips it to `canceled`
-        // with `endedAt` set when Stripe ends it at the period boundary).
+        // Cancel at period end, not `subscriptions.cancel()` (immediate) —
+        // matches the confirm dialog and the local-sub branch below. The
+        // webhook syncs the local row when Stripe ends it.
         await stripeClient.subscriptions.update(subscription.stripeSubscriptionId, { cancel_at_period_end: true });
         continue;
       }
diff --git a/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/route.ts b/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/route.ts
index 5590819da..1829010ac 100644
--- a/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/route.ts
+++ b/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/route.ts
@@ -67,11 +67,9 @@ export const GET = createSmartRouteHandler({
     ]);
     // Deprecated: map productId → subscription for backward-compat fields.
     // ownedProducts keys use '__null__' for inline products (null productId),
-    // so we normalize subscription productIds to match.
-    // In-effect (not active): a canceled-at-period-end sub still backs its
-    // owned product until `endedAt`, and must keep rendering as a
-    // subscription ("Ends on <date>") rather than falling through to the
-    // one-time-purchase branch below.
+    // so we normalize subscription productIds to match. In-effect (not
+    // active): a canceled-at-period-end sub still backs its owned product
+    // and must not fall through to the one-time-purchase branch below.
     const nowMillis = Date.now();
     const inEffectSubByProductId = new Map(
       Object.values(subMap).filter(s => isSubscriptionInEffect(s, nowMillis)).map(s => [s.productId ?? "__null__", s] as const)
@@ -133,9 +131,7 @@ export const GET = createSmartRouteHandler({
               subscription_id: sub.id,
               current_period_end: sub.currentPeriodEndMillis ? new Date(sub.currentPeriodEndMillis).toISOString() : null,
               cancel_at_period_end: sub.cancelAtPeriodEnd,
-              // A sub that's already winding down (locally canceled, or a
-              // Stripe sub with cancel_at_period_end set) can't be canceled
-              // again — the DELETE route would 400 on it anyway.
+              // Already-winding-down subs can't be canceled again
               is_cancelable: isActiveSubscription(sub) && !sub.cancelAtPeriodEnd,
             } : null,
             switch_options: switchOptions,
diff --git a/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/switch/route.ts b/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/switch/route.ts
index 36bc44c1d..5b7f4365a 100644
--- a/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/switch/route.ts
+++ b/apps/backend/src/app/api/latest/payments/products/[customer_type]/[customer_id]/switch/route.ts
@@ -112,11 +112,8 @@ export const POST = createSmartRouteHandler({
         customerId: params.customer_id,
       });
       // ownedProducts keys use '__null__' for inline products (null productId),
-      // so we normalize subscription productIds to match.
-      // In-effect (not active): this set classifies owned products as
-      // sub-backed vs OTP. A canceled-at-period-end sub still backs its
-      // product until `endedAt`; treating it as an OTP here would wrongly
-      // block switching for the rest of the paid-through window.
+      // so we normalize subscription productIds to match. In-effect (not
+      // active): a canceled-at-period-end sub is still sub-backed, not an OTP.
       const nowMillis = Date.now();
       const subBackedProductIds = new Set(
         Object.values(subMap).filter(s => isSubscriptionInEffect(s, nowMillis)).map(s => s.productId ?? "__null__")
diff --git a/apps/backend/src/lib/payments.tsx b/apps/backend/src/lib/payments.tsx
index 2ece10378..eb77d0bd6 100644
--- a/apps/backend/src/lib/payments.tsx
+++ b/apps/backend/src/lib/payments.tsx
@@ -117,13 +117,9 @@ export async function ensureProductIdOrInlineProduct(
 // were removed. All reads now go through customer-data.ts backed by Bulldozer.
 
 /**
- * Lifecycle/actionability predicate: the subscription is in a state where it
- * will renew and can be acted on (canceled, switched). This is deliberately
- * NOT the same question as "does the customer currently have the product" —
- * a locally-canceled sub keeps entitling the customer until `endedAt` (we
- * model cancel-at-period-end as `status: canceled` + future `endedAt`). Use
- * `isSubscriptionInEffect` for entitlement questions; using this one there
- * makes still-paid-for products masquerade as one-time purchases.
+ * The subscription will renew and can be acted on (canceled, switched). For
+ * "does this still entitle the customer" use `isSubscriptionInEffect` — a
+ * canceled sub keeps entitling until its future `endedAt`.
  */
 export function isActiveSubscription(subscription: { status: string }): boolean {
   const s = subscription.status;
@@ -131,18 +127,10 @@ export function isActiveSubscription(subscription: { status: string }): boolean
 }
 
 /**
- * Entitlement predicate: the subscription still confers its product/items on
- * the customer, regardless of whether it will renew. Mirrors Bulldozer's
- * grant semantics (subscription-start emits on row insert regardless of
- * status; subscription-end emits at `endedAtMillis`), which is why it is
- * deliberately status-agnostic: `canceled` subs stay in effect until their
- * future `endedAt` passes, and `incomplete`/`past_due`/`unpaid` subs that
- * arrive mid-Stripe-flow count too (they either transition to `active` or to
- * a terminal status with `endedAt` set — every terminal writer sets
- * `endedAt`, so `endedAt == null` means "no end scheduled").
- *
- * Accepts both row shapes so Bulldozer reads (`endedAtMillis`) and Prisma
- * reads (`endedAt`) can share the one definition.
+ * The subscription still confers its product/items, regardless of whether it
+ * will renew. Deliberately status-agnostic and `endedAt`-based, mirroring
+ * Bulldozer's grant timefold (grants run from row insert until
+ * `endedAtMillis`; every terminal writer sets `endedAt`).
  */
 export function isSubscriptionInEffect(
   subscription: { endedAtMillis?: number | null, endedAt?: Date | null },
diff --git a/apps/backend/src/lib/plan-usage.ts b/apps/backend/src/lib/plan-usage.ts
index 2a97b344a..83e1f803e 100644
--- a/apps/backend/src/lib/plan-usage.ts
+++ b/apps/backend/src/lib/plan-usage.ts
@@ -159,9 +159,7 @@ export async function readBillingSubscriptionMapOrSkip(
 
 function resolveActivePlanSubscription(subscriptions: Record<string, SubscriptionRow>): SubscriptionRow | null {
   // In-effect (not active): a canceled-at-period-end plan sub keeps its item
-  // grants until `endedAt`, so usage limits must be judged against that plan
-  // — otherwise this page reports "Free" while the customer's actual quotas
-  // are still the paid plan's.
+  // grants until `endedAt`, so usage must be judged against that plan.
   const nowMillis = Date.now();
   const inEffectSubscriptions = Object.values(subscriptions).filter((candidate) => isSubscriptionInEffect(candidate, nowMillis));
   for (const planId of BASE_PLAN_IDS_BY_TIER) {
diff --git a/apps/e2e/tests/backend/endpoints/api/v1/payments/products.test.ts b/apps/e2e/tests/backend/endpoints/api/v1/payments/products.test.ts
index 6d2df76ee..40f602c14 100644
--- a/apps/e2e/tests/backend/endpoints/api/v1/payments/products.test.ts
+++ b/apps/e2e/tests/backend/endpoints/api/v1/payments/products.test.ts
@@ -273,10 +273,7 @@ it("should report a canceled-at-period-end subscription as still in effect, and
   });
   expect(cancelResponse.status).toBe(200);
 
-  // The product must NOT masquerade as a one-time purchase during the
-  // paid-through window (it used to: the list route only recognized
-  // active/trialing subs, so a canceled-with-future-endedAt sub fell through
-  // to the OTP branch).
+  // Must not masquerade as a one-time purchase during the paid-through window
   const listResponse = await niceBackendFetch(`/api/v1/payments/products/user/${userId}`, {
     accessType: "client",
   });
@@ -286,8 +283,6 @@ it("should report a canceled-at-period-end subscription as still in effect, and
   expect(item?.subscription?.cancel_at_period_end).toBe(true);
   expect(item?.subscription?.is_cancelable).toBe(false);
 
-  // Canceling again must not claim the product is a one-time purchase, nor
-  // silently rewrite the wind-down state.
   const secondCancelResponse = await niceBackendFetch(`/api/v1/payments/products/user/${userId}/pro-plan`, {
     method: "DELETE",
     accessType: "client",