You were a little out on the details but you are on the right track with what you posted
Without taking into account low income rebates under the current discount method and assuming no other income you will pay tax on $12k gain on an asset that has been held longer than 12 months
The old system you would have been able to make a $30K ($25K at the tiem) gain before paying tax.
The new system clearly produces a lower amount of tax payble on large gains that have been made in a short (longer than 12 month) period
The old system it was as already stated, possible to pay less tax on gains upto approx $40K assuming no other income.
But the old system of calculating CGT could also create a lower tax payable amount on assets that had been held for longer periods of time, depending on the time held and gain made.
The new system encourages short term speculation and as a result higher volume of CGT transactions
