In the eyes of the ATO add up all your gains for the year = 350+300 = 650K
All up all your losses for the year = 250K
How much gains were made under the 12+month rule = 300K
50% of the 12month rule amount is = 150K
All gains minus all losses (including carried over losses) is what? 650K - 250K(yr losses) - 150K(carried losses) = 250K
From your final figure (250K) as it is profit and you have discount gains to apply you can only discount up to the maximum amount of the 12month rule (150K) or 50% of your total gains (250K). But it is whatever the smallest figure is.
In your case 250K / 2 = 125K (125K is smaller than the 150K)
You are now taxed on 125K with $0 capital losses carried forward.
