Depends how fast I drive I guess,
But by definition as they're calculating these figures before the plane has taken off, neither is this - it's a static calculation. If they already have some way of feeding that data into whatever system they're using ground side, then it could just as easily feed into a.n. other system shirley?
My understanding is this is just for calculating the weight distribution and CoG to make sure it's within static limits and to give the pilots the right figures to punch into the FMS.