Shipping Location Madness

Our vendors want to create a single, country wide flat rate shipping method.

Our cart includes locations for USA, each state and some more specific locations for tax related calculations.

CS-Cart is telling us that if there are any more precise locations created in our store, that within a shipping method, we have to add criteria rules for every single subordinate location.

This seems like madness. As I understand it, the USA has literally hundreds of federal, state and county or municipal taxes that could potentialy require locations to calculate taxes correctly.

Would vendors really have to create hundreds of redundant entries, just to set up (or edit!) something like a simple flat rate for the entire country?