I think you're asking about power because SNR is measured in decibels (dB)...not dBmV. Power is measured in dBmV.
There are ranges within operational specs: Best, Good, Operational and Out-of-Specs. Arris gave you the Best range. However, since Cox designed the network, only Cox can provide the Best range...albeit, 45-51 dBmV sounds great.
35 dBmV appears kinda low and could result in packet loss...then again, only Cox can provide acceptable signal strengths. Allan provided your cause so perhaps a Best range is coming soon.