Good Moring Chuck, thanks for your comments, of course I agree, you are EXACTLY CORRECT. Even though you already know all this just as FYI to others, HOWEVER I (as most others do) still use big Negative cables direct from my Inverter and Charger and Genset connected to the Batteries big main Negative Terminal/Buss VERSUS those currents returned SOLELY via the chassis/frame. I would never just run Positive Cables to my Charger and Inverter and DC panel and tie the other end to frame ground alone. Its just NOT in my Electrical Engineers DNA lol. I run BOTH Pos and Neg Cables to my main DC loads and to the Panel instead of using Chassis/Frame return. But HEY sure it would "work" (subject to connection integrity and resistances etc) if you ran ONLY the Pos cables to the Charger and Inverter etc and used Chassis/Frame as the return current path even though its NOT how I do it.
Fun chatting with you Chuck, take care be safe and Happy Thanksgiving