Wow, I got the (very public) Dell replacement battery last year for my 9300. I use it daily and it is plugged in most of the time, but my wear level is 42%!? I can't even imagine what my old battery is at, the one that was replaced for supposed "fire danger".
I will check the old battery right now and report back. This is bullshit, I am calling Dell first thing in the morning. I had been wondering why a full charge on my laptop immediately drops to ~50% full as soon as its unplugged from the wall... TOTALLY UNACCEPTABLE.