Need my upstream fixed; Arris S33; slow upstream (30 vs 300Mbps)

Had Xfinity install internet service yesterday, everything is working good except my downstream speed is slower than expected. I'm on the 2Gbps plan with rated speeds of 2000 Mbps down, 300 Mbps up. My average speed test results are showing 2,330 Mbps downstream and only 31 Mbps upstream.

The technician that performed the installation yesterday hooked up his equipment in place of my modem and he got 311 Mbps upstream, showing that the issue is with my modem configuration/internet profile. The technician said that a ticket would need to be opened to have this issue investigated further to have my profile/configuration updated, etc.

Modem is an Arris S33 that is certified for Xfinity and supports up to 2.33 Gbps - it provides 32x SCQAM/2x OFDM for downstream channels; 8x SCQAM/2x OFDMA upstream channels. 

My modem's configuration is showing full utilization of the downstream channels, however the upstream is being limited to only 4x SCQAM bonded channels. Support online suggested that the power levels are also a bit low for my upstream (averaging 40-41 dBmV) and should be at least 45 to 51-60 dBmV (range depending on number of channels).

I've performed numerous resets, factory resets, reconnections, etc. Still getting the same results from speed tests directly from the modem wired (2.5Gbps Ethernet). 

Any help with this issue would be greatly appreciated!