But somehow GSX is loading up 8201 KGS.
This is correct and it's intentional: quoting from the release notes:
Fuel quantity will be set and rounded up according to the customary rounding on the next hundred.
This has been suggested by users while testing, who objected refueling the exact quantity from the flight plan is not realistic, and it's rounded to the next closes hundred + 100 for precaution. So, 8087 kgs becomes 8200 kgs.
So, why 8201 and not 8200? Because in many cases you might running on APU so, if we set exactly 8200, the APU Realtime consumption would bring it down to 8199 immediately, since we can't set decimals from the FMC, so we set it to +1, which will result in the nice 8200, if the APU is running.
And yes, we might look into a small update to *check* if the APU is running, and not round up +1 if it isn't, this can be done.