Cancellation retention discount: offer life-time

Hey ​@andrew-moore-0bb907 - this is a current limitation of Customer Center. The "Cancellation Retention Discount" is built on top of Apple's promotional offers, which are subscription-only constructs. You can only offer another subscription within the same subscription group, and there's no option to map a non-subscription IAP (like a lifetime purchase) to that flow.

One approach you could consider, would be to control the entry point on your side and build that custom flow yourself. For example, when a user taps "Manage Subscription", check their CustomerInfo to see what they're on and, if they're a regular subscriber, open Customer Center as normal (and use the built-in promo offer flow) but if you want to present the lifetime option instead, route them to your own custom UI before Customer Center ever opens.

One thing to be aware though, buying a non-consumable "lifetime" product does not automatically cancel an active subscription. Apple doesn't allow developers to cancel a user's App Store subscription programmatically, so you'd want to clearly communicate to the user that they need to cancel their subscription themselves to avoid double-paying.