They didn't fall lower than #18, since #19 has been posted and UNH hasn't shown up yet. And they probably didn't move up given their season. So I'm betting UNH is still #18.
Oh, yeah, good point; I misread PC as 20th. Yup, 18th it is again then, as no way any team could earn enough negative points to fall below them; negative points appear difficult to be assessed no matter how bad a team.