Are you likely to be doing any other reno's/works in the next 5 years? If so have a think about whether to incorporate these into your permit application now. My understanding is there is a minimum fee and then a sliding scale depending upon the value of works - if $550 is the minimum anyway see what else you can get covered for same or slightly higher fee cost. In my area these approvals last for 5 years and so including proposed works now may may save having to lodge another application,and paying another fee, later.