According to the operating manual, page 42 it says... "Do not operate the tractor at full speed for the first 50 hours." It also says "not to start the tractor quickly or apply the brakes suddenly."
Some of the "Operating New Tractor" seems really bizarre to me. First of all, it might take me a year or more to get 50 hours on mine, or it might take 6 months, I don't know yet. Only had it a week but have a bout 4 hours on mine. And, what does applying the brakes suddenly have to do with breaking in the tractor since it is not a Nascar ride where the breaks need to be burned in a tad.
I mowed lawn the other day with it and I did not run it quite at full RPM, close, but not quite. I also have not worked it hard doing any loader work. Most of my loader work has been just pushing brush and moving firewood so nothing too strenous, and when doing that sort of work I have been running it at about 2500 rpm or so.
I think if you vary the RPM and don't work the snot out of it right away, it will be just fine.