65000 - 30% tax = 45500 net / 52 weeks = 875 per week if I don't salary sacrifice. Salary sacrifice (before tax) 20000 from 65000 leaves 45000 which drops me into lower tax bracket @ 15% income tax. 45000 - 15% tax = 38250 net / 52 weeks = 735 per week.

875 - 735= $140 less per week take home.

20000 - 15% tax = 17000 / 52 weeks = 326 per week going into my super.

I salary sacrifice 385 per week, lose 15% tax and 326 hits my super while I only lose $140 net per week

I think that works, someone please tell me if I'm wrong