How to create tiered discounts for monthly subscriptions?

[haydnspurrell]

We are re-platforming our monthly subscription management over to a Shopify and connected subscription app model.

I'm looking for something with flexible options for creating acquisition and retention flows. The use case I'm currently looking into is a strategy that offers a total value of $100 off across the first five months of membership. We'd break this down into the following pricing scheme:

First 5 months = $100 savings

Month 1 = $30 discount

Month 2 = $20 discount

Month 3 = $20 discount

Month 4 = $20 discount

Month 5 = $10 discount

I'm having trouble finding much information on this kind of model. It wouldn't be tied to volume, but rather duration of time spent as a subscriber.

Any thoughts on an app that might offers this?