Best practices for SaaS billing with Stripe

Hi HN -- hoping someone could help us understand the best practices for doing SaaS billing with Stripe.

We charge a monthly fee ($100) per "team" for the customer (w/unlimited users).

Customers can have different numbers of teams but it ranges from ~10-50.

I'd like to set it up so that there is a monthly subscription ($100 per team per month) but we also offer 10% off if you pay 6 months up front and 20% off if you pay 12 months up front.

So my question: In Stripe should the 6 month and 12 month discounts be SUBSCRIPTIONS or COUPONS? The 10% and 20% discount would be applied one-time (vs. prorated) so customer would be invoiced up-front in one payment for the 6 or 12 month block.

I could create a standard month-to-month and then customize the 6 or 12 month pre-payments based on # of teams the customer uses but then I'll wind up with many SUBSCRIPTIONS since each customer has a different number of teams, which feels messy...

Hope that makes sense -- really appreciate advice!!