Actually it should not really change things too much. You really don't want to be working on secondary applications before your MCAT test date, you need to be studying. When you do add all your schools, you should get the majority of secondary applications right away since you already have a MCAT score (with the exception of those few schools that still pre-screen). So during August you can fill out and return those before your MCAT score is released and you will be "complete" at most of your schools on the day your MCAT score is released. Schools won't review your file anyway until you have that second MCAT score, so no real harm done.
If you truly don't want to deal with all the phone calls, just pick a burn school, add them to your primary and don't bother calling the school nor returning their secondary application. Rush and Duke are a couple schools that come to mind that are probably used to applicants deciding not to return their quite lengthy secondaries. All schools cost the same on the primary application, and it's pretty inexpensive compared to what you will be spending in a couple months. Use the time to study instead.
