The transfer balance cap is a limit on the amount you can hold in retirement phase ($ 1.6 million in 2017 — 18). (ato.gov.au)
There is a limit on how much can be transferred to a tax - free retirement phase income stream, annuity or other guaranteed investment. (moneysmart.gov.au)
This is because they are beyond the saving for retirement phase and are now in the making - their - money - last phase. (money.stackexchange.com)