I asked the nurse isn't that trying to cheat the system, to make it appear that I have better clearances than I do
It is not cheating, as a higher BFR will give better clearance.
Check the filter they are using for you - the Fresenius ones come in 4 sizes (160, 180, 200 and 250). A bigger filter will result in better clearance. Fresenius requires that you fail clearance at 4 hours 30 minutes before your MD is allowed to prescribe a 200 or a 250 due to the extra co$t. Generally, heavier patients get bigger filters. I am a bit over 100kg and get a 180 when I am in-center (usually do it at home/NxStage), but only after asking my MD to increase it from a 160.
Why did you give up on NxStage?