I wouldn't trust that theory these days...This industry is chock full of morons that don't pay attention to what's going on around or in front of them and that are as likely to be texting or reading a book as they are to be looking ahead.
Knowing what I know, I wouldn't follow one of these idiot's at any speed.
They drive at a consistent speed because most company trucks are governed.
The driver sits there like a fool with his foot pinned to the floor all day trying to keep it at maximum governed speed, These assholes will go at maximum governed speed regardless of road conditions, construction or any other situation that a normal driver would use extra care when passing through.
Why do you think it takes 20 miles for these idiots to pass each other?
When one truck is governed at 62 and the guy he's passing is governed at 62 1/2 they will sit out there all day blocking traffic until they can finally squeak by.
The best advice I can give you is to pass trucks as quickly as possible and stay as far from them as possible because while many of us are good drivers that do our best to be safe and courteous, a damned near equal number are ******* that shouldn't be allowed to stand anywhere close to a big truck, much less, drive one.
Sadly, Truckers ain't what they used to be