I own a John Deere Z225 mower (42") and I've been having problems while mowing. When I used the mulching feature, the grass clumped up and I had to mow over the lawns twice. Just recently I removed the mulching kit and changed to using side discharge. I mowed my lawn with the side discharge and I also had to go over it twice. I've noticed that most professional companies use side discharge and they have no problems, the grass doesn't clump, and don't have to cut twice. I mow at 3.5". Is there something I can do so I don't have to mow twice?? Thanks.