Electroid, not sure if the card can be returned, cause technically, you could use all 100 cd upgrades on the card and then say you don't want it. When you get them back no one knows whats left on it.
I have the chips with 30 cd upgrades on it and I actually mark it down on a post it each time I use one. That way I have an idea when it runs out or is getting close.
Usually, I just mark the post it and cd that I did it with out the a/b check. The other night I zapped the Doors new remastered 40th anniversary cd and did the a/b comparison. It was a nice improvement. Jims voice was a little more pin point with better detail and clarity. I am hearing morrisons voice on the new anniversary cd with several cd tweaks like I have never heard before.