We are looking to implement a feature that allows merchants to charge customers for changes to a prepaid subscription that would require it. A few example use cases:
A customer wants to increase their quantity from 1 to 2 after 2 orders of a 6 order prepaid subscription. We would need to charge them the cost of 4 orders of 2 quantity + the difference in the shipping rates of those orders.
A customer wants to add a product to only their next order. We would need to charge for just that item on that order.
A customer changes their shipping address to an address that has a higher shipping cost. We would need to charge for the difference in shipping multiplied by the remaining orders.
With the fulfillment orders that a prepaid subscription generates we are having a hard time coming up with a solution. It wasn't the approach for standard subscriptions to have orders created beforehand so we're not sure why this approach was taken here. If our app was able to make calls to createBillingAttempt on each order still it would be feasible to accomplish it that way.
Was there a way that your team envisioned this being done? For sure it's a non-trivial operation but it's flexibility that merchants have come to expect from a fully featured prepaid subscription.