PC, current live (9.0) as well as 1.04 PTS version.
The reference point for the third person view seems to be assigned to the rear axle. See the following screenshots of a DAN and M916 as a long and short wheelbased trucks.
Both are zoomed in to the max. The M916 has no load option, but you can see across the cabin. Forget that with the DAN or other long trucks. And the twinsteer as well as the fat / long KOLOBs with a massive cabin are even worse.
Edit: Screenshot from Imandras Container transport as the DAN bounced up:
If you have a tall cargo or a tall&bouncy trailer, the camera may even be disturbed by the load and "jiggle around". See
If you would move that reference point with respect to the front axle, you could avoid that issue. Scroll closer to the front axle and thats it. The load should not interfere with your camera again. And as the front axle is typically your steering, the perspective should be similar regardless of how long the truck is. And you could have your above and behind cabin view regardless of the length. And by the way, the collision issue of the cam with bouncing trailers would be also solved.