Just want to say, that my RE does b/w to test for the surge, and once they detect it, they tell you to BD every other day for a week (I think most people just do every day for the 2 or 3 days around a +ve OPK, so it would definately be worth extending the BDing!
When I was having u/s every couple of days they were doing b/w as well. I had an anaphylaxis reaction to the puregon and so we stopped it and was supposed to wait for AF to arrive so that I could start again. I had the opks already so I figured I would see what was happening. At CD14 my follies were 10mm and 7mm so things weren't looking good but that was a week ago. Today is CD 22 so we will see.