I charted with both my pgs. For the first I ovulated on day 29. The CNM humored me and put MY due date on the medical charts, but somehow when they sent out the AFP they used the 14d cycle edd and as a result the results came back with a red flag. It took some doing for me to convince the genetic counselors to run the afp numbers with MY dates, but when they finally did the risk of problems was very low. Then when my due date neared, the CNM said she wanted to induce me if I went past my due date (which would be 42 weeks according to the wheel). So I'm not sure whether anyone ever took my word for it and would have honored MY due date. Fortunately, my 8# 7oz baby arrived naturally a couple days before the due date I had calculated.
With my second pg I ovulated on day 21. This time the CNM (same one) recommended an 8 week u/s to "check dates". I thought it was unnecessary, but figured it would be better than arguing on the other end about whether I needed medical intervention to bring on labor. I refer to it now as the "pre-emptive u/s". Of course, the u/s confirmed MY edd of the 22nd, but later I had to correct the CNM's paperwork because they STILL had it down as being the 17th. For this and many other reasons, I ended up planning a homebirth instead. I got the flu at the end of my pg and after days of fever, congestion, aches and coughing, I coughed so hard my water broke and I went into labor. Baby was born soon after at home at 9# 2oz on the 14th (a week earlier than MY date!). So go figure.
The moral of the story? Forget the dates! Or at least stick with the latest ones you can so you won't be bullied into medical interventions. And psychologically, it's a bummer to go 'past dates' but it's a pleasant surprise to have the baby arrive 'early'!