Got me. Maybe I have a "special" MT.

The times I listed were combined file time. For instance, each time was a combination of 2 times (the first file in the 24/48 test was somewhere around 1:55, with a second file at about 47-50 mins- the 16/44 was about 3 hours 7 mins for the first file, then 17 mins for the second).
I have recorded 15 bands using the MT, ranging from a quick 30-40 minutes (festival sets) to 3.5 hours (using a backup USB battery box for the last hour or so, just in case). Maybe that isn't enough use to have the battery life degrade?