[Brian Pfleuger]

Digital scales have to filter their output. The number they give is derived from a calculation based on the voltage passing through a metal bar. The item you're weighing is pressure down on the bar, which induces a voltage change. The voltage fluctuates constantly and the scales software has to filter small changes or the number would never be stable. Some scales "stick" when you slowly add weight basically because the software sees the slow change as background noise and filters it out.

A quick Google search tells me that this issue has been reported with Scheel's scales.

I don't know what your budget is but you could save yourself the time and effort of manually trickling charges by going with an RCBS Chargemaster Combo or the similar Hornady version.