ACCC comparison table shows Sydney airport carpark is most expensive at any airport in Australia ($50/4hrs, $15/1hr), however omits the 15min free pickup. Also omits that Sydney Airport staff forced to visit the ACCC headquarters must pay $21/2hrs, and $72/4hrs at the ACCC building.
That last part may be true. But the ACCC doesn't own or operate the car park, nor does it participate in the profits generated by the operator of the car park. And there is a plethora of optional ways to travel to the ACCC, or places to park in the vicinity of their office.
Melbourne Airport is a greater scandal. Virtually marooned, the transport options are extremely limited. No trains, precious few buses. $80 by taxi to or from the Eastern Suburbs. And not a monorail in sight.