Athena,
I took mcat in april, then again in aug. In my situation, w/ horrendous scores in april, I've found that it has actually been to my advantage to retake. I don't think I would have received UC 2ndaries based on my april scores. In the meantime, I'm working like crazy to try to finish all the 2ndaries before end of September. The UC's seem to be @ a month behind east coast schools in scheduling interviews, so that's good for us aug mcaters. On sdn, I've only heard of 1 UC interview so far (SD).
Most schools are definitely waiting for scores before scheduling interviews. Don't fret--I know of hordes who are only now submitting amcas! Our timing's fine. It'll be Oct. b4 ya know it! Actually, I wish sept wouldn't fly by so fast, since I still have so many 2ndaries to finish!!!