This post has sparked my thoughts so I compared my Digital Scale (that came with my WTL Amadeus GTA II) and my Shure SFG-2 Stylus Gauge. They are different. The digital scale reads 1.52 Tracking Force and the Shure scale reads abou 1.48. I think I will believe my Shure SFG-2 Guage. Though it does sit a little higher from the platter so maybe it all evens out and they are both accurate?
If the digital is like one of these jewelers scales......https://www.amazon.com/Proster-Turntable-Backlight-Cartridge-Brilliant/dp/B06XP27LCR/ref=pd_lpo_vtph_267_tr_img_2?_encoding=UTF8&psc=1&refRID=QQGF56ZTF1C6K414V9M8
.....I'd trust it over the Shure. Calibrate the digital scale by weighing a US nickel. It should be exactly 5.0 grams. A US penny after 1983 is exactly 2.5 grams.
I do believe that for uni-pivot arms the digital scale will be fairly inaccurate if you place it on the platter. For reliable results you need to remove the platter and place the scale on something such that its weighing platform is exactly at record height.
I did the comparison -- digital scale on platter vs. off platter -- with my uni-pivot arms (when I had them) and the VTF results were quite different.
With gimbal / fixed bearing arms the digital scale can be placed on the platter without much loss of accuracy. With my 3 gimbal arms the VTF is about .05 grams heavier vs. removing the platter and getting the scale platform to exact record height.
BTW.....what makes you think you can get your stated accuracy (to the hundredths of a gram) from a Shure balance scale, simply by using your eye? I have one and the method in theory seems perfect but in practice strikes me as kindof crude, and I surely wouldn't trust my ability to read it that precisely.