Thanks for the information. I called back and asked for a supervisor to get the low down on the rules. I was told that if you are upgrading an International or Transborder fare the airline does NOT charge the $145 change fee. But if you are upgrading a DOMESTIC fare, you are. The supervisor said that the rules are quite different for the different fares, but essentially you get "shafted" the most on domestic items.

Looks like I'm stuck with a L ticket and no chance to upgrade