I didn't have to worry about the number of follicles with our IUI because it was cancelled when Clomid caused my lining to thin out. But with our first IVF cycle our FS would only allow 1 ET, we pleaded with them for 2 ET on our next IVF cycle and we had to sign a waiver form before they would consider it. But that IVF cycle we ended up cancelling also because of OHSS and getting really sick. This FET we are on now, we wanted 2ET but the FS wouldn't allow it, seeing how we have had complications previously. I think it just depends on a case by case basis and the rules and regulations of the clinic you go to. Good luck with your cycle, hope you get a BFP