S!
The perking of N1k2 is a question of history and numbers, but also a question of balance.
Quite simply a N1k2 matched up against a P-47D11 or F4U-1 is not a good match. Against a Hellcat, the N1k2 also would be dominant.
We do not have the F4UD in this Scenario, we don`t have the P-47D30, we don`t have the P-51D, not to mention we don`t have the C-Hog. These are all the natural historical opponents for the N1k2. They aren`t in the Scenario because they are `44 aircraft.
The two U.S. `44 aircraft included, the P-38L and F6f5 do not have huge performance advantages over their `43 counterparts.
And the other Japanese planes are quite up to the task of fighting any of the Allied planes in the setup.
I will fly Japanese more often, and personally I think a Ki61 Tony will kick D11 and F4U-1 butt. The Hellcat is a good match for it. They are both very similar in performance, with the Tony having a little better turn and the Hellcat having a little more speed. The P-38L would give it trouble if it is flown smart, but the high speed maneuverability of the Tony will make the Lightning look like a cargo plane if U.S. pilot isn`t careful.
The A6M5 is also vastly underated. A single Zeke can make a mess out of a bunch of low Allied planes.
Sabre could also have allowed the B-17 to be unperked. That wouldn`t be out of line with history, but likely would unbalance things.