David, Thanks for your quick reply. Yes, the AC compressor behaves just the way you describe.
PBU stands for climate control's Push Button Unit. Sorry for not clearly state it. Item 7 should be pressure reading, I have no idea what should be correct value either. When in compressor off mode (EC) the value is about 4.5-5. Maybe it could be a clue to system leak. Need expert like Steve B to answer for us.