I own a Encore Premier 36 WB, Model 283702, which I purchased in July of 2002. It has given good service but I have always had a problem with Dallis grass in my lawn which sends up seed heads on a long stem. The deck of my mower pushes these stems over and the blades go over them. This causes you to have to go over the same area several times to get them all cut. I have three spacer shims on top of my blades which lowers the blade to 7/8" above the bottom edge of the deck. Can the blades be lowered any lower or is there another way to fix this problem?