How Do You Measure VTF?

Does antiskate affect VTF? I measure the VTF in different points of my scale & the measurements vary. I have my antiskate active during this time. I used calibrated weights on my scale at different points and the weight remained constant. This was done using a point source as a weight. This was referenced on a $1500 diamond scale (too big to use to check VTF). My cheapie scale is within 0.01 of a gram consistently. I am guessing I should disengage AS prior to determining VTF. But... does a cartridge manufacturer want VTF determined w. AS force taken into account as part of the cumulative VTF? Any ideas.