EPA MPG estimates for 2,3,4,5 year ventures?

In shopping for a new venture there seems to be discrepancy for the epa mpg ratings? Do the 4 and 5 ventures get 17/24 rather than the 19/26 of the 2 and 3 vans?

Here's info I have (I really think they are all the same eng/trans combo, right?

1 18/25
2 19/26
3 19/26
4 17/24

I guess this was for the AWD models , 4 and 5 are still 19/26 mpg. Yea.