If you have a newer engine with DPF/DEF pollution controls you will want to run the engines hotter, low idle operation worked well in the old equipment but not so much in the new.
I seem to get the best fuel economy running a steady 2200-2500 RPM on my HST machine instead of using the auto-throttle. 12-14 hours on a tank vs 10-12.
I seem to get the best fuel economy running a steady 2200-2500 RPM on my HST machine instead of using the auto-throttle. 12-14 hours on a tank vs 10-12.