I just bought the Lesco Commercialplus Hydraulic Renovator 20. It seems to me that the slicing blades leave an excessive amount of grass on the surface. I've tried going over the lawn with the slicer blades only (i.e., not applying any seed) first, then picking up that grass with a mower, then go over the lawn again with the slicer blades and the seeder component. There's still quite a bit of grass left on the ground. Is this just how the process is going to work or am I doing something wrong? I adjust the height of the slicer blades to just make contact with the ground. Thanks for any input/feedback.