I've got a mouse pad that charges my mouse wirelessly. When I use my little digital scales on it to weight my weed, it goes mental. The electrical field most certainly does interfere with scales. I have to move the scales well away from the mouse mat to make them work accurately again.

I'd say to test accuracy would be to try it on a mouse, cat, or dog.

The test has too many variables going on. But, this does have potential maybe? He should use an old fish scale for measuring weight changes. They do use a spring.