If the high side pressure tap isn't at the compressor, but further down the line, you could have a restricted condenser or receiver, and if the high pressure tap is after the restriction, it can be mis-leading. We recently went thru that with another thread, the fitting was blocked.
With the low side going into inches, the compressor is moving refrigerant, but it seams slow to make it back around to the suction side.
With the correct amount in the system, and the compressor moving refrigerant, it almost has to be a blockage somewhere.
Receivers are supposed to be sized such that they can hold the entire charge within the receiver in liquid form. For it to do that, the pressure has to be high enough to keep it liquid.
If you can feel the hose/tubing, you want to start at the compressor where it is hot, and feel along until you feel a marked temperature change, and that will point to the restriction.
When all else fails, I add ( Piercing) taps to the hard lines so I can take pressure reading at several point in the system, once the problem is resolved, I replace the sections that I added taps too. It seams drastic but can save you chasing your tail and replacing things on a hunch.
If you have a charging scale and an amount, you are way ahead of most people who have problems. At least you KNOW what is in there and what should be.
I will add that I am trucking, and only check in once a day if that, so If I don't respond right a way, I will at some point.