One thing to remember is the cap is determined by the top 51 contracts on the team.
When each drafted player is signed they knock down one current player off the top 51.
So for example, Dallas currently has Francis Bernard at #51 with a cap hit of 780k.
When the 10th pick signs his deal, he'll boot Bernard out of the top 51 and the net charge would be from you example cap hits of 3.58mil - 0.78mil = 2.8mil effective cap hit
And so forth unless a pickee has a smaller cap hit than the new #51 roster player.