In short - Sentinel Hub’s quota management is not yet integrated with “Hectares under management” model. This is why the number is set so high that it should not cause problems. If you will continue downloading data over the same area (I certainly would if I were you, as there is value in there), and the quota will actually go to 0, we will simply increase it.
This goes the other way around as well - there is currently no technical limit preventing you to consume more than what you purchase. You should take care of this yourself, knowing which areas you have under management. If you will exceed the limit, we will ask you to repay for the overage.
We are planning to integrate the quota limits better, so this will eventually be clear.
As a side note - we storngly recommend to use Subscriptions with PlanetScope data:
By doing that, you will also have a simple view in all the areas under management, directly in the Dashboard.