My mum and sister booked a cheap package at the Hard Rock through the Go Holidays website.
You can't select to include pre-booked luggage in the package deals. My sister called the Australian Air Asia contact number, and had someone throwing up all kinds of different prices and could barely speak english.
She got told if she turned up at the airport they would be charged $8 per kg of luggage. She asked to pay the $2 fee for 15kg luggage but was told it wasn't Air Asia's problem call Go Holidays on a Malaysian number.