BCP equalizing size of embryos?

One RE told me that it didn't matter if i went on bcp or not before cycling and another RE said that she would prefer me to go on it for like 2 weeks before bc it helps in leveling the playing field so that all the embryos start to grow at the same time and are even in size when cycling? ANyy thoughts on this theory?
Thanks!!

i was told that bcp is necessary because when taken before pgd cycle it would prevent growth of a single egg (as it usually happens in a natural cycle). Instead, taking bcp, followed by lupron and stims, will allow you to grow lots of eggs that will be similar in size.