Anti-skating question

I recently installed a new phono cartridge (DynaVector 10x4 MkII on Origin Live modified Rega RB250 on Planar 3 table). At first, I set the anti-skating force so that on a spinning grooveless record surface the tonearm would pretty much stay where it was set down or drift slowly outward. That, I assumed, was a pretty good and direct way to set the level of anti-skating force needed. Then, I put on HiFiNews&RecordReview’s test LP and used the anti-skating tracks – basically, you adjust the anti-skating until you hear no tracking distortion of the test signal in either channel. This procedure gave me a very different setting – one that does not counter (not nearly totally, anyway) the inward skating of the tonearm when set on a grooveless record surface. I would have thought the two methods would have produced more similar results. Any explanation for this? (I’ve stuck with the sonically-based setting for now.)