Not sure how you can drop 3,000 RPM between shifts when most diesel engines are governed to around 2,100 RPM.
13 speed to 9 or 10 speed you gotta make up the difference somewhere. RPM drop between gears is the only place you can. You gotta get up to speed with less gears.
He is just over thinking it. Tell him to treat it as a standard H 4 speed. In other words up- down-up down- split-up-down- up- down. No need to ever go all the way over to the left unless using reverse or need a super low gear. Easier than a ten. Tell him it's nothing more than a H. Other than that as others have said forget about speed it's all about rpm and listening to the engine.
OK were just looking at the same numbers differently. There the same. It's just I've been around trucks my entire life, got my cdl on my 18th birthday. There isn't much I don't know about trucks or business of trucking as I have been around both. I've had 3406 cats.8V92T Detroit's, Cummins small cam, big cam. Horton fan cluthes and international oil over air fan cluthes. Air ride, 4 spring Pete and me. Truck. Torsion bar KW. Most people have never heard of these things, so when you questioned me it rubbed me the wrong way. Sorry.
I was a company owner for 25 years. Spent 5K a month on rubber. Tore Cummins down Friday after work, blowing smoke by noon on Sunday.
At 21 to 18 rpms my truck would have stalled out a long time ago. My truck runs in the general area of 1000 - 2000 rpms, with an rpm drop at shifting of roughly 400-500 rpms.