You are right bob. Rto gives max system pressure (assuming you're not antiskid limited). Theoretically max manual and Rto are the same, however in practise it is very hard to achieve the same stopping distance with manual braking due to the fact that a pilot will inadvertently reduce brake pressure whilst turning and a secondary effect of that is that the antiskid system will continuously work to find the correct level of braking thereby increasing stopping distance.
I think you're trainer may be mixing up Rto and auto brake max.