OC and Cool N Quiet

I have OC'd my Athlon II 630 to 3.5Ghz on air on stock settings., P95, OCCT and CPUStab stable with temps getting to 48* on the CPU and 42* in the core under test load. Otherwise at idle I am hitting 28* at idle while hitting 38* under load at night during the day these temps can jump as much as 7*(I have poor air conditioning in the house). Which brings me to my question. WHen I use C'n'Q while over clocking my idle temps drop by as much as 3*c.

I can understand the necessity for disabling it during the tweaking process, in fact that is what I do. But if during normal operation after final tweaking C'nQ doesn't create an unstable system then why not leave it on? Is there some magical reason for this?

I forgot to ask, or perhaps sugggest, that if you have a high overclock that perhaps the low end of CnQ at .975 volts might be too little voltage for the low end(ie if you have an OC at 275*4 the .975 might be too little to keep it stable at the low end).