Be it CCRM, ORM, or even Kato from Japan, the FET rate is always better, even with UNTESTED blasts.
Here is the reason. First of all, you must make high grade blasts before your blast can be frozen. My clinic, L.ife, only freezes blasts above 3bb, if you make 3cc, you are outta luck. Early blasts or compacting morulas won't be frozen. This is pretty much the same standard as all other clinics with a strong FET practice. The high grade blasts have a much better chance of surviving intact after thaw.
Second, your uterus is in a much more receptive state when your body is not pumped with hormone.
However, this does NOT up your chance of live birth, this ups the chance per transfer for live birth. It is still UP TO YOUR OVARIES to produce the high grade blasts! If you can produce quite a number of high grade blasts, yes, this is definitely the way to go. In the end, it is still about YOU.
Btw, the 90% thaw survival rate is a bit low, my clinic runs at 97%. I am just curious if he is saying 90%ish or 90%, because 90% thaw survival is mediocre at best. You'd expect 95% at least. HFI is running at 95%, and CCRM claims 98%.