This sounds suspiciously like a “fraud on the minority” or whatever the correct legal term is – basically it’s a majority decision that falls within the rules of strata law but which is quite clearly intended to benefit one group of owners to the detriment of another.
So, firstly, I think it falls outside the remit of strata law – and that is a good thing. Your next move should be to chat with a lawyer about taking this to the District Court or even the Supreme Court where, unlike with the CTTT, you can have both costs and compensation awarded (if you win).
I’d be looking to have all unfair payments refunded, backdated to when you first claimed, plus the costs of taking the action, plus an order to draw up a by-law removing the car park payment from the levies and making them part of a payment to the admin fund – as well as a commercial parking fee – payable by all of those who are allowed to park there.
Free parking is a luxury enough without forcing owners who don’t have this benefit to pay for part of it.
Talk to a lawyer, get an estimate of how much it would cost to run a case and then get the other non-parking owners to chip in to a fighting fund.