Any way to adjust Cable Modem Downstream Power Levels?

My internet connection has been terrible for the past two months. I have had a technician come now and nothing has been resolve. After researching around the web, I believe the issue is due to the power level my cable modem is receiving (see attached). Are the power levels normal? If you're unable to see the picture, the power levels are all between -10 to -23.

Is there any way to adjust the power level?