So, TTi says my Hookers are made wrong, are they full of crap?

I have 2.5"TTI on my Duster with HP 340 manifolds and it bolted on with no issues at all.
I first had a 360/727 auto with column shift, now its a Magnum 360 with A518 OD. ---same exhaust.
I also have 2.5 TTI on my 68 383 4spd Road Runner with manifolds and no issues there either.

My good friend put TTI on his 440 4spd 72 Runner about 3 or 4 years ago and had the same issue you appear to have. I believe his headers are Hooker, but I'm not sure.
on one side the pipe bend missed going on the header by more than 1/2".
He called TTI and told them the problem, they asked for the measurement and bent up a new adapter to fit and sent it to him.

At a few shows, I've spoken to different TTI reps at their vender tents.
Some have been friendly and very informative and a couple others couldn't care less to talk to me.
Maybe you got the jackass when you called.[-(