Do you have a hundred piece stop? And does keeping a count of that many work for you? By the time you get to 100 and the board says you've only scanned 99, do you assume you counted correctly?
I have a stop like that, and there are a lot of things going on that make it nearly impossible to keep an accurate count in my head. I make sure that I scan each package as I unload it. It takes a little longer, but not as long as rescanning all the packages.