1.5 cm difference in saddle height is a lot. I notice 5 mm but can compensate to some extent by moving around on the saddle.
WRT to my fitting, my problem was a twisted torso so to speak. My left sit bone was forward and more center on the saddle and the right cheek was more rearwards and almost off the saddle. My power balance left to right was 45/55% and the big issue, my left hamstring or the muscle that attaches to the greater trochanter would get very sore as in painful on a hard effort of say 10-12 minutes. Her changes have helped a little. I am closer to 50/50. I am a little more centered in the saddle but do not feel planted.
I need a new comfortable frame with around 405 mm reach and about 610-630 stack. My current frame is 396mm reach and with that I need 150 mm stem. I have a 135 or 140 in there now, it seems ok. Not easy to find a 150 mm stem.
Long story short, the fitter felt my position was giving me problems and also I needed to see a Chiro......I had fractured my Great Trochanter so no surprise the muscle connecting there gets painful when climbing moderately hard. Complicated post but there could be two things going wrong as is apparently my case. I never ever had these issues in my past. Determined to solve them.