I have 146 doff.
When I'm in klingon academy. If I meet imperial klingon officer to convert green doff to blue doff. It says it's missing one doff. If I want to convert blue doff to purple doff. Again it says It's missing one doff. How it can miss doff? I have 146 doff? 10 purple, 10 white and others are green or blue.
Is it bugged or what?
There are certain DOFFs that you obtain that cannot be converted because it'd just make it too easy to make your entire crew Purple just with a little bit of grinding.
Most of these DOFFs are the ones you've bought from the duty officer NPC.
"My frozen dairy-based confectionery attracts all the males of the species to the facilities. They all agree on it's superiority. Indeed, it is superior to yours. I could teach you the finer details but that would require monetary recompense on your part." -The Milkshake Song: Vulcan Edition