Audio Additives Stylus Force Gauge inconstantcy

I recently purchased an Audio Additives Stylus Force Gauge and it is driving me nuts. I get inconstant readings every time I lower the stylus onto the little black dot on the plate. Without moving the arm, every time I lower, raise, lower, etc., I get a different reading between 1.68 - 1.88. The batteries are new, device reads 0.000g at start up, calibration checks out using supplied weight, room temperature is 72F, no interference from tonearm lifter and everything is level.
Anyone else have this problem?
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The body of the Riverstone gauge---they actually make two, but get the one with the extension arm which puts the stylus at playing height when measuring VTF---is made of a tough plastic, and that extension arm of a non-ferromagnetic grade of stainless steel. The gauge has resolution to 0.005g (!), and can be recalibrated to zero via the 5 and 20 gram weights included. Riverstone Audio has a video on You Tube in which the gauge is displayed, described, and explained, and then demonstrated.

The ubiquitous electronic gauge that most companies are rebranding and marketing as their own is, in comparison, a piece of junk, regardless of price. Many of them sell for more than the Riverstone, some much more. I mean come on, $28.95---whaddaya got ta lose?! For more details, see the Riverstone Audio website. 

Did you set the anti skate at 0 before you did the calibration?
Here ya go!
Another possibility is that it’s telling the truth, as in bearing issues with the arm.

No mention made of the type of tone arm.  If a unipivot that possibility is out.
Just switch to the good old reliable Shure SFG-2. Never goes out of calibration. 
The Transcriptor scale is perhaps the nicest vintage scale 
I have owned and built like a fine instrument.

That said I still need to have batteries in the drawer for
the more modern options.