Riding Lawn Mowers

My 46" Husqvarna tractor mower has 6 deck settings. When I put it on settings 1, 2, and 3 the deck sits on the ground. On setting 5 the mower cuts the grass at 2 1/2 inches. Was this deck installed incorrectly? As of now, the first 3 settings are a waste as they can't be used unless you want to till a garden.