There is a points cap in Central of 39 points for 15 players (total points reduce if only 14(37), 13(36), 12(35) etc).
Imports are 12 points and starting (20mins plus) NBL players 10 with some discounts for loyalty and if your junior club.
Most players are 1 point
If is basically impossible to sign 2 imports at 12 points each and an NBL starter @ 10 points and fit under the points cap.
Also 10 & 12 point players are categorised as restricted players and clubs are limited to no more than 2 such players.
I thought all the NBL1 leagues used the point system with maybe some slight variations.
There is no salary cap in NBL1 Central