This isn't a huge deal, but I thought someone should be made aware of it.
For some reason, Major Drills is incorrectly over-counting the vending when he gives you that as a quest. For example, he just asked me to vend 6 times, which I did. On his quest page where it shows how many times I've vended though, it says 19. I had a quest earlier that had the same thing. The count on Major Drills' page was 31/10.
This has been reported here: Major Drills&; Quests