In the download section, specifically in "Portal 2 Maps and Files", I see (shortened):

SP
Coop
PTI
WIP
Other

I use the PTI section because all my maps are created with the PTI puzzle creator. When I upload to that section, on Portal 2 Maps, it places PTI maps in the SP section. I have 5 Coop PTI maps. Should I upload PTI Coop to PTI, Coop, or should there be another option? Like so (shortened):

SP
Coop
PTI - SP
PTI - Coop
WIP
Other

Quick answer; Yes it should be updated.

We put the PTI category in the night before the PTI was publicly released. When we knew coop wouldn't yet be included. If you make PTI coop maps; for now just upload them to Coop! If we change it to make more categories we'll move them.

I've been working on an updated system that is supposed to be better working than the current system and allows more flexibility and information but unfortunately due to the nature of the current system and lots of other factors it's a highly complicated thing. It should make uploading maps much simpler, faster if it's workshop maps and it should fix any confusion on where to upload what. However I have no idea if and when it'll be done.
The problem is that the current system is a monster. It is a total pain to fix the system.

Good. I didn't want my PTI coop maps removed from the Coop section that is clearly Hammer made maps or get in trouble without confirming it is OK.