Oil consumption problem

[DINANM3]

I have a 2006 4,4 and a 2004 4.4.

I have 33000 miles on the 2004 and it has not burned a drop of oil between changes since new.

Now my 2006 currently has 6000 miles on it and ive already had to put in 2 quarts and its a little low again.

So I go to the dealer and tell them and they say its normal and by definition combustable egines burn oil. So I say bullshit then how do you figure that my identical 2004 has not burned a drop yet. He just stared at me like i dropped a bomb on him. The guy had no clue. He just continued to say its normal like he was a robot programed to say that.

So what is really going on hear. Does anyone know why its burning so much oil and how 2 exact same engines can be burning oil at such a different rate. 1 burns non and the other burns a quart every 1k
Any help will be appreciated and advice