Had a conversation with the MBF, the gist of it:
-current rule doesn't allow the fund to force a member to claim on work cover (or TAC etc)
-new rule has changed that so they can, or at least withhold payments if they think you should be
-both the current and previous rules mean that if receiving WorkCover periodical payments you will NOT receive MBF payments. Once work cover payments stop you can claim MBF.
-if on a permanent disability leading to loss of licence a WorkCover/TAC etc payout was "unsatisfactory" you could then claim from the MBF. Not sure who's definition on satisfactory is used.
-Whilst receiving payments from WorkCover/TAC/etc the MBF will NOT top up payments to bring in level with what you would receive from the MBF even though they acknowledged it would be significantly less.
Now I might just be too cynical after dealing with insurance companies but this seems to leave the fate of your payouts on good faith rather than clear rules?