So I bought version 4 of this software because I read that filenames can be customized now. So I have a file called Event_001.NEF and after processing I would simply have it named Event_001.dng. But it always makes Event_001-NEF.dng. I want to keep the Filname, sequencing, etc. I made in PhotoMecanic and JUST have the new .dng Suffix, there is no need to write in the filename that it once was a .NEF file. I really hope I’m missing something for a version 4 Software 
I agree, find it irritating that the file renaming keeps the original extension. Hope they can sort this in an update.