No, I really don't know how you're adding it up.
If I go by Spotrac's numbers it's 7 years at $113,450,000 which averages out to $16,207,142 per season.
If I subtract the final 2 years and make it a 5 year deal, then it averages out to $15,640,000 per season.
I only see roster bonuses in the earlier years. I don't see anything that goes away in the later years other than base salary if he is cut.
Regardless of how much he is restructured, you have to include the restructure bonus money in the overall amount paid out. If he is cut after 5 years, then the total amount paid out was
$78,200,00. Dividing that by the number of years that he was on the team (5) gets you the 15,640,000 number. Yes, you could push some of that out as dead money with at June 1st cut, but including years that he is not on the team is not really averaging out his true average cost per year of service.