Having only 3 mobile AA platforms in the game it is going to be easy to pick which one is easiest to use.
If the game only have the Spit16, Spit9, and Spit5, which one would get used %90 the time???
If anything (and w/o looking them up), change the ENY of the Wirblewind to 5, the Ostwind to 20, and the M16 to 30. Forget adding a perk cost.