𝓒𝓞𝓒𝓚

[glossy breach]

Hi there 👋 I think our Billing Thresholds functionality might be what you're looking for.
https://stripe.com/docs/products-prices/pricing-models#usage-threshold

It allows you to set either quantity or amount thresholds that when crossed will automatically trigger the creation of an Invoice.

The only part I'm not sure of off-hand, is if this will fit your requirement of generating an Invoice every X number of units (currently I believe the threshold can only be triggered once per billing period). However, you can use our Test Clocks to run through a simulation of with this functionality pretty quickly and confirm if it does what you're looking for.
https://stripe.com/docs/billing/testing/test-clocks

[tired echo]

Thanks!

[glossy breach]

Any time!