I picked up my mulch kit today and asked for 2 sets of blades. The blades I got are flat, without the hump in the middle like the blades that came on the mower. I'm figuring this will make it mow 1/4" higher but what about cut? I mowed the first lawn tonight and had some clipping coming out in clumps. I also noticed that some grass had not been cut. I'm wondering if the flat blades are causing the tips to be too high above the deck> Should this be a problem or is this what I should expect?