Not if we refuel under the left wing...
Assuming the airplane loads from the right wing...Yes of course, we could always add something like allowing if the refuel happens on the other side of the loading but, if it's not the refueling, it's the catering which can conflict.
At present it impossible to do a sector return on a 3 to 4 hour leg in 30 to 35 minutes because of the delays occurring because of this restriction.
Yes, everything can be improved but, I wonder how you'll ever be able to use GSX before ( it was like this for years ), when NO kind of concurrent service was even possible.