Bennett did get significantly more money, I was just looking at first year with my initial reaction.

Martellus Bennett signed a 3 year, $21,000,000 contract with the Green Bay Packers, including a $6,300,000 signing bonus, $6,300,000 guaranteed, and an average annual salary of $7,000,000.

Jared Cook signed a 2 year, $10,600,000 contract with the Oakland Raiders, including $5,000,000 guaranteed, and an average annual salary of $5,300,000.
Jared Cook turned the Packer offense around last year, IMO.

The initial page I hit had JC listed as a better FF prospect than MB, but I see now that most sites had MB rated 10 slots better among NFL TEs.