Bi-polar PC

While I have been amused by the completely unrealistic battery expectations of the T135 I am becoming less amused when it throws things in the other direction. I was beginning to worry a few minutes ago as I was told that I had 60% remaining on the primary battery, and that meant that I had 2.5 hours left…. WTF? I wasn't doing anything, the hard drive was inactive and the fans were quiet. I decide to ignore the battery situation and just let the thing go about its business… check on the battery level again after a few minutes and then I'm told I have over 6 hours of battery remaining. I really wish this thing could calculate based on the amount of battery that I use on average to determine how much time to put on the clock. So far this system is performing well and I haven't felt like I will be needing a longer lasting battery, but the jumping around bit gets to me. I prefer feeling secure in the availability of power on my system.