Of course they didn't, who is arguing that? The OP stated 1500lbs, his rig apparently weighs in at 1200lbs.
Do us a favour and sell the truck and tow with the Buick, let us know how you make out. Also, I'm sure you know already but you'll save more gas if you stay IN gear going downhill then you would by using neutral
Like I said, I find the whole 'if you don't have a truck you shouldn't tow' attitude.. Definitely good for a few laughs.