The Gravel Bed Settling Issue has been solved. Somewhat at least. We never heard back from Clement Rose, so Peter decided to call Todd who engineered our New Septic System, et voila, the next day the hole was filled up with new gravel (by Clement Rose) and so far nobody thinks that there is anything wrong with it. It's just soil settling -Todd will come over and check it out to make sure. We redirected more of our drains too that will be buried in spring.