As the Hub displays the first 9 downstream channels initially, it would not be the first time, by far that only the first 9 downstream channels have been posted, always worth a check.
I see your primary downstream channel is on 299MHz and Channel 9 is on 227MHZ. I just wonder where the channels on 235, 243, 251,.259, 267, 275, 283 and 291MHz have gone,? unless they are hiding further down the page
If the number of downstream channels have dropped from the usual 20 \ 24 to 9, might have provided a tiny clue why downstream speeds are dropping and certainly worth mentioning. I am not sure if the CMTS is even can broadcast a 9 channel downstream bonding group as they are usually grouped in groups of 4. Due to load balancing 371Mbps would not be achievable with only 9 downstream channels.
I agree that only 2 16QAM upstream channels may be problematic on a 350Mbps pacjage, pending the loading on the local circuit. However, there is nothing in your logs to suggest the upstream is in any distress. It would be highly advisable to start a Broadband Quality Monitor to get a deeper insight on how your local circuit is performing.