So it seems like you need to manually set the voltage and frequency setting(s) after flashing the new firmware ..... that would perfectly explain the dropping hash-rates then ...
Yeah after all my late night fun last night I'll just stick with October's release for now. LOL
Hindsight is always a wonderful thing ... and with that in mind, it looks like the first port of call for dropping hash-rates would be the freq settings, but yeah, I don't blame you for sticking with your reset firmware seeing the only officially documented change is the reset button functionality.
Anyone still running the new November firmware, would you please find out what version of cgminer ships with it?