I'm new to the tractor world so I have been reading a lot and noticed several threads about reducing RPMs since these tractors have a radiator and do not need full throttle for cooling. I decided to experiment and reduced my 1023R with 54"MMM to 2600 RPM just because it sounded good at that RPM. After 5 times of cutting grass I plan to stay at this RPM because I see no difference in the cut quality and the fuel consumption reduced significantly. Also a noticeable lowering of the temperature.
I have a flat yard with a mixture of grasses, not a lawn, but I take pride in making it look good and I am very pleased. So unless the more knowledgeable say there is something harmful to the tractor you may want to experiment with your yard and tractor.