I hadn't thought about this until now. I installed my current shunt in the negative battery lead to the fuse box also, per meter installation instructions.
I think I remember a ground strap between the gen and the gen chassis pan which is bolted to the TC.
I haven't had the time to calibrate the meter readings so also hadn't noticed that things didn't add up. I'll have to investigate. It may be more accurate to install the shunt in the positive leg of the battery.
Also will keep up with this post to see what others have done.
As to why, I can only guess that the gen may create static noise. Connecting the gen chassis to camper chassis may help filter the noise.
