I was told not to worry about the power levels unless they go above 15.
Though it's only the extra 10 Downstream levels which are showing over 10 the other 10 have never been above.
I find that very strange, usually -6 to +10 is the range.? I take it you have no problems with your broadband.?
Things don't suddenly stop working at +10 dBmV. The -6 to +10 dBmV downstream range is to allow for varying levels of SNR down to 34.5 dB.
The higher the SNR, the more out of range the power levels can be and still work well. So +11 dBmV at 38 to 40 dB should be fine as the SNR is very good. Each 1 dB increase of SNR is an order of magnitude better than the last. 43 dB SNR is insanely good.