I have tried 3 different digital scales and all have the same problems. I have turned off all the flourescent lighting, cell phone and stereo in my shop. I have no fans and don't breathe/blow on the digitals and place them on the same spot on my bench every use.I have warmed the scales under a incandecent desk lamp, kept them on for several minutes and still got "zero" variations and nearly impossible trickling up (going very slow readout can and usually does, jump .2 gr heavy. ). My solution is to calibrate before any use, "tare" frequently, and double check against one of my beam scales. When setting up powder charges I use my beam scales (Lyman/Ohaus D5 and RCBS 5-10 which are checked for zero every session.). I get the target weight and put it on my digital. Quite often the weights will differ slightly but since the digital is a bit faster, I'll used the weight shown on the digital as the "target" for the digital. Often double checking with a beam scale. For a load workup I weigh every charge and keep charges (hand gun cartridges) to .1 grain and this is the best method for my using of digital scales...
Consistent powder charges isn't merely a safety issue, but an intrigal part of reloading; "double check everything". Having been reloading for about 40 years using my "Go slow, double check everything and most important, have fun" philosophy I have had one squib (1971) and no Kabooms...