Thing is in a senior social team what extra costs do AFF (or capital) or any federation face for players 17-18-19-20 etc. only 16 can play in a game so if teams have casual players or players who only play 2/3rds of the season that's a club and player issue to sort - it dosn't increase the feds cost one bit.
Instead having teams with 16 players only will mean more defaults, more postponement requests - less enjoyable competitions and therefore less value for money.
AFF did say the NZF regulations said it has to be a per player levy hence me asking people around NZ if that's whats actually happening.