Docsis 3.1 question

I'll presume you have a DOCSIS 3.1 modem.  Did you notice the 32 Downstream QAM channels?  QAM channels used to be single channels (SC-QAM) separated by "guard bands."

With D3.1, although you see only 1 OFDM channel, it's 1 channel divided into 32 QAM channels but with orthogonal separation.

Could you post a copy of your modem logs for a better understanding?  You may have to use the Click-to-Join link at the bottom of this page to upload.

Do you mean UNcorrectables or correctables? Lots of correctables on OFDM is normal because of the way OFDM uses FEC. Even up to 100% correctables can be considered normal. But UNcorrectables on any channel and any modulation is never normal. If you have UNcorrectables it means there's a problem with the data getting to your modem. You should never disconnect or connect the coax cable with the modem powered on. This will cause a large number of uncorrectables.

As far as I know Cox only supports 1 downstream OFDM channel and 0 upstream OFDM channels at this time in all areas. 1 OFDM channel is more than enough to support fill gigabit speeds.