Alright Bkthunder, I finally had some time to sit and try it out.
I tried to replicate your parameters, all in landing configuration and in my experience there is a small difference in rate of descent, which however can be compensated (in SPS off situation) with about 5-10 % throttle advancement. Based on the manual there should also be about a 2 deg AoA decrease noticeable on the UUA but I couldnt observe that. However I could feel the greater tendency to fall (not sure if I'm using correct word here, but I hope you can follow).
I'll try to search for better references for that.
As for the %, well if it was 80 % than based on the manuals I have it is not correct, as system limitations are fairly well described in original document, thank you for reporting.