You can take up to your SIS upper limit at any stage after leaving the public service.
To access the remainder you have to fully retire.
One last point. Once preservation age is reached (55 years for your vintage)your first $140k of taxable component withdrawn from super is tax free. That is not to say it is not added to your taxable income. You simply get a lump sum offset for the tax that would have been paid on the $140k.
It would be worth checking the break down of the CSS lump sum between untaxed, taxed and non-taxable. As there is different consequences for the above components.
