As you can see from my previous "belly shot" I definitely do not have that setup. It would be interesting to find out whether Jayco installed it on some units and why. Your fuel supply and return lines do look the same as mine, so I imagine the stock basic fuel delivery/return system is the same, with an added-on crossover.
From my experience the installed system (on my rig) still passively levels the tanks when running the generator without the chassis engine running. I also find that when I refuel I start on the passenger side, and by the time I get to the driver's side the level in that tank has risen from when I first uncapped it. Not fast enough to fuel only from one side however!
Reading online it seems new Class 8 trucks use the dual feed/return system, but I can't find any reference to an actual DOT regulation restricting crossover lines on new trucks. But you can find stories of tire "alligators" eating them causing big messes, and my personal work experiences back that up.
Would be nice if we could solve the original issue of inaccurate fuel level gauges!
2014 Seneca 37TS
Toads: 2014 Ford Explorer Sport or 2013 Ford Focus ST