I have to admit, I have never tried the zero-on-hand thing, so I don’t know about that. I was always curious what location it uses. Primary bin? What if there isn’t one.
Serial-tracked parts are interesting as the tags are printed based on the location in Serial Number tracker and NOT the quantity in a bin. So if you are missing serials or have extras, you can get some wacky results. But you said it’s not a serial problem. So that’s just FYI.