I hadn't thought of all these years.
(I've generally tracked the weight registered when I remove the pan to dump the powder. If/when that wanders (>0.1), I reset zero and press on.)
Surprisingly, I've found that a slightly different empty-pan zero doesn't appreciably effect the final powder net weight... since the machine recal's on that new zero and the added powder weight is measured relative to that
I'll now go plug a VOM into the wall socket and watch the summer rollercoaster.