No, they do not charge to revise.............If you added ANYTHING extra to those revisions, ie. extra category, bold type, reserve, etc, then those do have fees attached to them.
BTW: Every single time you revise an item, it starts the "indexing" process all over again..........Meaning it could take up to 24 hours for that listing to appear in search.........Keep your revisions to a MINIMUM
You do NOT get charged a Final Value Fee until the item sells of course..........how would they know ahead of time what the end amount is to charge you?
Any fees you are seeing on an invoice are for PAST sales........
http://pages.ebay.com/help/sell/fees.html