Hi dean lenertz, and a warm welcome to the forum. It's great to have you onboard
As you will see on the Scotty 45, the height range is adjusted by the rod that is attached to the lefthand arm of the front roller with a locknut. This rod moves through an elongated hole in the mower side-frame. This range of travel has been set by the manufacturer to be optimum for most types of lawn; bearing in mind that the bottom knife blade assembly (which is fixed) should remain as close to parallel with the ground to ensure a correct cutting action.
To increase the height beyond this range may tend to 'tilt' the bottom blade somewhat and thus affect the cut.
However, if you screw the adjusting handle down to full travel....see if the rod has reached the top of the elongated hole. If it has, filing the hole with a rat-tailed file carefully may give you that extra 10mm you are looking for, and check to see if it affects the cut UPDATE: 05April 2013....After some research and talking with qualified greenskeepers, any modification to the original height settings of a cylinder mower is to be discouraged at all costs....Please DO NOT carry out this modification.
Please do not PM me asking for support. Please post your questions in the appropriate forum, as it helps all members, not just the individual member.
Kindest Regards, Darryl