The taxable / tax free components are based on the source of the funds. If a tax deduction was taken on the way in then it and ALL earnings are then the taxable component. Only contributions from post tax paid is the tax free component.
Once a pension starts the % of the taxable / tax free component is fixed.
Example - start of pension 50% taxable with a balance of $1m.
In the first year assuming a min 4% draw-down, then $20K is tax free and $20 taxable.
Now you have a great year and now in the second year the balance has gone to $2m, and still on 4% min. Now you have $40 taxable and $40 tax free.
So the % is fixed, but the actual amounts will vary depending on the returns, or lack of in the pension account.
The biggest game in town, is to reduce the taxable component before you start a pension if at all possible by re contributions, selling and buying lose making investments to cystalise the lose (this come out of the taxable component).
