Another TS-520 question... If I calibrate the VFO movable ring at lets say 175khz, then I move to 350 khz, I see a up to 3 khz difference. That difference appears to change as I go through the range, as in it might be high at 250, then low at 350 compared to the 25 khz cal reference. Does that make any sense? And is this something that can be adjusted?