My setup is 27Lb, on a G11, and I have it balanced as best I can. I Keep the one 21Lb counterweight as high up as possible. It does seem to help. Same thing for me with NINA TPA and then PHD2 tells me I'm a little higher. Should be no worries on that. Are you doing a Calibration and Guide Assistant before every run in PHD2? You could run a 20-minute Guide Assist and see how it performs over time unguided. Here is a pic of where the 21lLb weight ended up on my setup.?
David Malanick