This isn’t a pre-paid gas pump use, but that could be one way to present it. We all want to fill as fast as possible. And if your fill spout can handle top rates, you get top fill rates, until you close in on the hard limit. Then it trickles down to the metered drop. Then stops precisely where it needs to.

By accepting/requesting a hard cap, the provider can make clear that in order to be precise, soft caps will go into affect earlier and induce progressive throttling where applicable. If the throttle doesn’t catch the final milliliter or two of gasoline, before the pump shuts off, the provider can and should just let it go. It’s a loss, but comparatively a figurative drop in the bucket.

The other obvious route is predictive where prior usage guide the guardrails. Ordering two eggs is typical for a single meal. Ordering twelve is not. Ordering three or four is unusual for most but if you are a regular diner your habits will be observable.

Any of this predicated on the provider to want to do something. They seem to lack incentives at this point for making it easy. It is stories like op that I avoid well known problematic providers like Firebase who don’t respect and foster long term relationships.