There is also another problem with your search, CCHAN needs to be CCHANS, CCHAN no longer works correctly. It was changed to CCHANS a update or 2 ago. Unfortunately unless I mis-counted that would put your search at 52 chars after you correct the PAINS one as well. I recently started using the show type=series choice as well and it does help eliminate some unwanted matches.
When you say "no ;longer works correctly" does this mean at all or 'iffy'. The couple of searches I've set up that use CCHAN seem to be working OK, i.e. limiting selections to the specified channel, but am I just lucky so far?