Replacing Hard-Coded Parameters

Snapshots seem like the way to go. Normally I would suggest a master table of the 40-50 parameters but you have an unusual situation here where you don't seem to be adding child records to your master record. If this were say a typical billing situation where you had a parts master with prices and an order and you were creating order lines than the typical set up here would be to add an order line choose the part number into the join table and look up the current price and then have the corresponding snapshot field.

But it sounds to me like you don't want to have a child records on your form so I guess it does make sense to have one master table with all of the various permit fees, in one record. Those would all be looked up, all 40 of them as look up fields into your data entry record and then each one would have a corresponding snapshot field.