Unfortunately, setting separate permissions for different purses is not something that any version of Uniprint currently supports. No such need was ever anticipated; it was assumed that the power to credit and debit user balances (other than through normal charging) would be limited to a set of people who could be trusted to use that power only in accordance with the organization's policies. Maybe somebody can come up with a way to modify the system to enforce such a restriction, but it isn't obvious to me.
In case anybody thinks of adding a Billing Plug-In to the Pharos Remote Bank, that won't work. The Pharos Remote application works through this Bank only for logging on.
Not sure what your campus environment is like so the following might not be applicable; however, if your campus utilizes a billing system besides Pharos (e.g. Blackboard Transact, etc.) it's possible to use that billing system to manage the print quota thereby nicely preventing the use of Pharos Remote from being a tool that can be utilized to manage adding/removing funds from the purse. This of course has a list of pros/cons associated with it. We've been using this method of years with success.