I had same issue as yours. I posted question saying that notification is not showing up in Windows7. After posting the question here, I did try to find the problem and I found that even my battery life jumps same as yours from 25%-6%. After looking at your question, even I thought my laptop battery life is over. But, somehow I wanted to retest it again by changing some settings in the Balanced power mode and surprisingly it started working fine after changing couple of settings. If you look at my question Brian suggested some finding on net about this issue, so I tried to modify settings to get the notification after that it never jumped from 25%-6% again. Now, my laptop is working fine and notifying me when it reaches 10% and hibernates when it is at 5%.
As the answers you got from techie007 and others I'm not sure whether they should be accepted as is. I'm saying this because as soon as I shifted from XP to Windows 7 this problem started. I was bit lazy in finding the problem so I let it go for a month or so without investigating. But yesterday when put up a question all these findings have come out. Since then I was continuously testing my battery with full charge to completely dry out, it never jumped again. I'm not sure about your case, but in my case above answers doesn't apply to me and it might be a bug in the Windows7 OS. May be to get more clarity I need to switch back to XP, but I cant to do that at this moment.
One more addition to this reasoning is I've got 3 same laptops bought at the same time and all are having XP on them, they are still working fine only my laptop got this issue by switching to Windows 7.
May be I can check this by switching other laptop to Windows 7 in couple of weeks. I'll update it after that. Hope it works well.