It's stupid really. It's must be the way the programmer wrote the code. But basically the system uses a subset of the selection criteria up to the number of hits allowed. I.e. if hits are set at 500 records, it first gets 500 records, (inspection lots). (I believe it's only using the selection profile and maybe date range at this point, not the plant, material, batch, etc.. selection values)
It THEN applies the selection criteria to those records only. As a result you get unwanted records in the first pass and if your plant doesn't happen to have it's lots in that first 500 records, you won't have any records to put the selection criteria against.
Craig