Seems to me that when a hub is first published (in my case), the score will get into the 90+ and upper 80+ for a good while, then once it has been published for a while, the score will begin to drop. I am assuming that is normal. As all of my hubs have done that since I started HP. I guess after everyone has read it who is going to read it, reads it, then the traffic will drop. I have also noticed that highlighting older hubs, helps to bring more traffic in, as well as going and reading a hubber you have not read before and commenting and possibly following every couple of weeks, helps traffic come back to hubs, and the score may go back up a bit. This has just been my experience.