Are you sure Florida taxes are charged based on the recipient's location, not the shipper's ? Most states don't do that, and as far as I can tell Florida is not a participant in the SSUTA (interstate agreement to standardize taxes by calculating them based on destination).

FWIW, we have a much more difficult situation here in WA; in July we will be changing to destination-based sales taxes, but ZIP is NOT sufficient to calculate the tax. You must actually look up the full address, since taxing districts don't follow town, county, or ZIP boundaries. Furthermore, the state doesn't provide anything in the way of support for automation. No web service to tell us the tax rate. Oh, there's a 750,000 row CSV address table they will give you, but you still have to do a JOIN on a second rate table to find the actual tax rates, and the tables are updated every quarter so each merchant is responsible for completely reloading his own DB or facing penalties. The tax table is many times larger than my entire store DB, all for a variation of a few tenths of a percent rate across the state.