Things like this are what make outside reviews all so important. Sadly I've yet to read a 757 review which goes into any depth as far as systems or performance, instead most are focused on the beauty of the AC and thereby somewhat misleading.
FFS,  I do hope you can go back and give the FMC a closer look to see if you can reproduce the problems many of us are seeing. Try also to take a look at fuel burn and compare it to RW 757's, as well as performance comparisons between the 3 models CS offers. And please if needed make the necessary amendments to your review  ;)