The building in question has all the sanitary sewer lines converge into a single 4" leaving the building. It's 2 stories with second floor restrooms stacked on top of the first, a total of 12 fixtures plus 2 more joining in from the lobby.

Basically everything ties together using a double wye which (according to video) looks to be sitting kinda flat causing a small amount water & paper to hang there. Clogs are generally caused by feminine hygiene products and can be dislodged with an auger but the surface of the pipe looks a little rough after 9 years of service so we decided to hydro-jet them to remove the scale.

Contractor shows up and jets the pipe, he was done by the time I arrived due to meetings. I was surprised to find that they could only jet about 40' of pipe which had to be accessed from a clean out outside the building. They jammed the jet head backwards through a 4" clean out and ran it up into the problem area claiming thats the norm and if you run the head from an inside clean out it will backwash and flood the space.

So how the hell do you guys in the biz hydo-jet any significant amount of pipe, like 200 to 300 ft from multiple clean outs, with these machines?

Depends on how much hose and what kind of machine and head they used. They probably didn't even get the scale off the walls either.