I think you are measuring (and mistaking) crosstalk for channel balance. If using the test record, channel balance is track #1. Center, left or right depending on lights on foz. I do not know why you can't get the reading to move. Sounds to me like your cart is just not aligned correctly to begin with. On my arm, I can get the fozgometer to move about 2 points either way with a simple azimuth screw. If the cart is improperly aligned, you'll never get there though with a "micro" adjust.
What are you using for alignment?
How much antiskate are you using?
I'd start over... sorry.
What are you using for alignment?
How much antiskate are you using?
I'd start over... sorry.