Question on REW rebuild

I recently rebuilt a REW motor, housings refurbished by freelance, intake and exhaust ported, all new seals and springs, mirror finished removed from side plates by Lynn Hanover method. The engine is back together and while turning the motor over by hand there is a notable drop in compression on the front rotor, 1 face only. I am going to pull the motor back apart to see what the problem is. I assume it's a side seal issue. I was having a problem getting some of the new file fit side seals to spring back out of the side seal grooves and put some of the old side seals (longest I had) in the rotor with a clearance of 0.0075. I know they are supposed to be between .002 and .006 (max 0.015). While this is the issue that I will check on first, is there anything else that I should look for? Is it normal for there to be some discrepancies in compression before the motor is broken in? Any help on guidance would be appreciated. thanks