Nevermind, I read that wrong. I see what you are saying now.

I have seen that formula before. The problem is that it doesn't consider pin weight. On an F-250 You will max out on pin weight long before you get to the tow rating you get by using that formula.

I'm sure you could pull one of those gooseneck car haulers that fits 3 cars, but you would really have to watch the weight distribution. 3 cars would probably be OK, but trucks or SUVs you could probably only haul 2 at a time.