I have a small yanmar traoctor which has for number of years served as my mowing machine, and gardent tractor. I have struggled for some time using a plow and a disc for soil prep, and when I found a good deal locally on a kubota three point tiller, couldn't refuse. Love it, but not sure I have it adjusted, and or using it correctly and could use some help. When I make a pass, on the end where I start, it makes a big hump of soil, and when I get to the end of the pass, it leaves almost a trench. Is this just to be expected, do I not have things adjusted correctly, or not using it correctly?