It's also very possible to have some productive contractions without really feeling them. I have non stress tests weekly due to complications and the monitor picks up contractions that I can't feel at all. When real labor hits of course they'll be much stronger... but they could be helping me dilate right now and I'd have no idea.
You do not need contractions to dialate. I have some girlfriends who have been dialated for weeks. I'm 40w2d and only a fingertip dialated and I've had contractions with no progress on dialation.