simplistically, there is NO tax on any earnings inside pension phase super accounts. nobody can TRANSFER more than $1.6M (atm) from accumulation accounts into a pension account. the $1.6M pension account cap is a TRANSFER cap, it is NOT a balance cap ..... but when first introduced it sorta was a balance cap cos some had more than $1.6M in their pension accounts so these peeps had to get rid of some through a couple of choices that were offered (this CANNOT happen again in the future).
example, i only transfer $1M from accumulation into a pension account. if this pension balance then grows to be $2M over time, i still have the option to transfer another $600K into the pension account from an accumulation account (cos i never used the original $1.6M cap amount).