Hi Dave,
Well, I don't want to alarm you since we audiophiles can get a little obsessive compulsive, etc., but I've been using a Shure VTF gauge quite a bit lately and it doesn't behave the way your setup is behaving. On mine, the results are very repeatable (for the same tests). I've been using it recently with a SME tonearm and not only does the gauge read the same every time, but the markings on the SME arm correspond almost exactly with the gauge. So, I guess it's possible your gauge is "gummed up" - one way to find out would be to get another gauge; if it reads different from the first one then you likely have a gauge problem; if it reads like the first one, then you might have an arm issue. Hope some of this helps.
Well, I don't want to alarm you since we audiophiles can get a little obsessive compulsive, etc., but I've been using a Shure VTF gauge quite a bit lately and it doesn't behave the way your setup is behaving. On mine, the results are very repeatable (for the same tests). I've been using it recently with a SME tonearm and not only does the gauge read the same every time, but the markings on the SME arm correspond almost exactly with the gauge. So, I guess it's possible your gauge is "gummed up" - one way to find out would be to get another gauge; if it reads different from the first one then you likely have a gauge problem; if it reads like the first one, then you might have an arm issue. Hope some of this helps.