CraigLewisYet many kitchen scales are still not accurate. My Soehnle returned a value of 134.xx, 137.xx and 141.xx grams when I weighed my Galaxy S6...
DriventomadnessIf you were allowing the reading to settle in each time, then I'd consider the batteries. Or some variation in the conditions...not quite level surface, that sort of thing. Sounds like you want a calibrating weight, and see if the company offers up some calibration testing procedures. May be time to talk to them.