Very low Upstream signal

Several months ago my (Cox’s) modem was damaged by a power surge.  It was replaced with an Arris TM3402A.  Since then I’ve had no problems.  Download and Upload speeds are good 180 down and 12 up and Downstream power is good.  However, Upstream Power Levels ALWAYS remain between 23.50 and 26.00 dBmV.  I know that this is MUCH below the desired level, but I am experiencing no problems.  Should I be concerned?  Should I get a tech out here to check things out?