If contributor spends balance in store, value of balance increases.

Accrued balance is 'worth more' the moment it is used for a purchase rather than paid out. Don't really know how that is supposed to work. Maybe a depositor can see in his account that he has 10€ balance if paying out in cash. But that it is 11€ if he deploys it in the store. Or: 40% if spending and 33% if cashing out...?
Very curious how other store owners look at this as well.