The only other possibility I can think of is that there may be some oil on the cylinder walls from doing the rework. The extra sealing that it would cause may bump the psi up a little (or Kg/CM

).
Have you tried running the engine yet? If it is oil (I mean a thin coating, not liquid) it will go away after running the motor.
I\As I think here, are the ring gaps O.K.?
But thats about it.
Funny, most people have trouble with low compression.