How to get COX to fix the low upstream power being provided to my address.
That Arris support page is the source of so much confusion. Long story short, ignore it. It's wrong. For example, the upstream power on my SB8200 is 37 dBmV and my connection works flawlessly.
Now for more explanation. First, upstream power is not supplied to your modem. Your modem supplies upstream power for communication back to Cox. The Cox equipment tells your modem how much power it needs to use in order for that communication to be received. If the upstream power is 41 dBmV, that means the Cox equipment is receiving your signal properly with that power level. Higher power levels would just be a waste.
Your modem communicates with the Cox equipment 2 to 3 times per minute to establish the correct upstream power level, so if any adjustment is necessary it will happen automatically within 20 to 30 seconds.
The only thing you need to worry about with upstream power is if it's above 51. That means there's a problem since your modem is having to "scream" just to be heard by the Cox equipment. But if the power is low, that's not causing your problem since if the Cox equipment needed your modem to use more power, it would ask it to do so.
You obviously have a problem with the connection, but it's not the upstream power level and it's probably not the modem. Post an example of your signal screen and modem logs after the modem has been running for at least 24 hours. That will help to identify what the real problem is.