I can only answer from a player side, not the club side.
I believe the ZL fees are slightly higher than All Age, as I think there may be a comp entry fee.
But I think at least at our club the final rego cost to players ends up being pretty similar.
I rego'd for Zone league this year, total $410 which had
FA - $33
NNSW - $133
Macquarie - $50
Club - $194
I don't know what the all age rego total is for sure but I would estimate $350-$400