Our payment scheme basically is "freemium" where customers are only charged after they grow to a certain size. Most of our customers will have a $0 monthly bill. We will only enroll the customer with CG the first time they expand past the free level (too keep our initial signup fast and simple), so only paying customers will show up in CG normally. These customers have a tracked item "users" which tracks how many seats they have used beyond those included in the free account. (Note: this means they are not "free" accounts in the CG sense).

However, some fraction of those paying customers will then stop using the extra services (these are software "seats", and sometimes the customer will shrink). When a customer shrinks below the free level, their usage charges will be $0/month. Business has asked me to confirm whether these customers will generate a "transaction fee" each month (my understanding is no, but I can't point them to anything that explicitly says so).

Generally speaking we would prefer to leave the customer on-account, in case they grow again. However, if they are generating charges each month (and at this point they don't generate revenue, of course), we will likely cancel their subscription and force them to re-authorize when they next grow.