This is how I have heard it explained a couple different times. When starting pct your natty Test is tanked, so you don't also want to tank your E. Some E can keep mood and libido and even emotions stable in a somewhat unstable time. And allow your body to a period to balance on it's own. Obviously while using a SERM to keep it from binding. But add an AI around the third week at a moderate dose, and run it out a couple weeks past your SERM while tapering down for the rebound prevention.
Now, I don't know if this is bro-science or real science. But I have done it this way a couple times and it always "feels" right and has worked.
