Ok, now explain how to handle the situation where a user that has been grandfathered into a new set of features and kept paying the original price is at a tier

Ok, now explain how to handle the situation where a user that has been grandfathered into a new set of features and kept paying the original price is at a tier limit and they downgrade halfway through the period they have currently already paid for. Downgrading would put them over a tier limit, so they can't be automatically downgraded unless they first delete enough stuff to be within the next tier limit down. Then I suppose they need to get a credit on their account or a refund etc. But do they get new pricing or are they still grandfathered or what? Not to mention if they are a South African customer their invoice needs to display the VAT subtotal in Rand and Stripe etc don't cater to that. That's on you. This stuff becomes kinda nasty when the edge cases stack up and there isn't anything in the market that handles it all beautifully. That'd make all our lives a lot easier. SaaS billing still sucks. It's good to see some discussion on how to handle some of this stuff. Information is really thin on the ground.