Why does my DVR do that?

Ok...so B and I are watching The Bachelor Pad (I know, I know...but we can't help ourselves). And we had to run and switch laundry and get a snack and stuff, so we paused it, because that's what you can do with a DVR. So...then we hit fast forward to speed through a commercial and boom, suddenly it's at the end. So we rewind, and boom it's back at the beginning. Say what? The only way it would work is if we fast forwarded it very, very slowly. So that's what we did. Then I hit fast forward twice..by mistake and we had to start the process all over again. I give up. It's taken us 3 hours to watch a 2 hour show and in the end it's the Bachelor Pad for pete's sake!!