Blades How to level grasshopper 618 mower deck

My mower deck manual for my 618 grasshopper with a 52 in deck states that the back of the mower deck should be .375 in. higher than the front of the mower deck, That would make the front of the mower blade lower in the front and higher in the back, that I believe is correct, However the front of my blades are are .750 lower in the front than the rear. Are these the correct dimensions? and if not how do I adjust the mower deck? I have 21in. tires and use the 2nd mounting hole on the mower frame.
thanks Dave T

Blades How to level grasshopper 618 mower deck