I normally find them by the date modified column within Microsoft explorer.

I will create archive folder within each company data folder.
Great! Then we just need to Process all new Files, then move them into Archives. This also takes care of the multiple midstate files. As well as handling things anytime someone forgets to Process the files.

It also eliminates the need for File Names and Name Patterns.

Business Rules question: Does it matter, if midstate files are processed in bulk, that sometimes your Outputs don't have any midstate Data and other times they're full of it?