Agree with NE.
Select all the quads you can see in the critical area and press "-" (dash). This will hide them and reveal the guilty
. then simply delete it (them) and press "\" to have all your polys back in display...
As for the Subpatch vs CC, I recommend to use Subpatches. Infact the CC will generate a way more dense mesh (1:4 ratio at Level 2, 1:16 at Level 4. 1:1 when SubD Level 4 and CC Level 2).
To verify it, set the same level for both, draw a cube and hit TAB. Then press CTRL-d to "FREEZE" the model and hit "w" for statistics (with Polygons enabled). You can easily count the polys generated by the two SubD types.
Hope it's clear enough,
Dario