It's strange that you would get changing downstream channels, i don't think i've ever heard of anyone being able to change them with resets, you would be the first, odd...
Well the monitor just shows that the modem was reset, i've seen similar changes in the past when i've switched upstreams, but not quite as noticeable since your graph is practically one of the best i've ever seen after your resets, can i move in with you?