Dana,
Yes, there is an inversion in the signal path, I was referencing the input to the first stage.
You studied the final amp stage, can you see why the gain can not be increased independent of the offset? The two adjustments seem to cancel each other out, the end result being the required gain can not be achieved, it is always about 1 percent below required. There is some type of negative feed back in this circuit that is not apparent to me. The design looks straight forward however is flawed, and the flaw is beyond my comprehension.
Regards,
John