So it turns out the Thunder did renegotiate Perk's deal this year… and in turn they gave him a deal that will ultimately be worth just under $9 million per year. That's $11 million more over the course of the extension than the Celtics could have given him. Woj also reports there are clauses which could add more money to the deal.
Shrewd move by Sam Presti in OKC. Perk probably could have gotten more but he filled a need and he did so without breaking the bank.