The AAT said, at para 42:
"The question comes down to one of characterising the credit card administration fee – either as a stand-alone fee in itself, or as part of the “underlying” tax, fee or charge that the credit card is being used to pay. We think that the fee is correctly characterised as part of the fee for the underlying supply. The person procuring the supply is buying, for example, a parking permit. There is one payment. In a practical sense there is one supply. This is the “practical” (see Saga Holidays Limited v FCT  FCAFC 191; (2006) 156 FCR 256 at ; Sterling Guardian Pty Limited v FCT  FCA 1166 at ; (2005) 220 ALR 550; and Re AGR Joint Venture and FCT  AATA 1870 at ) application of the tax. This is the interpretation which is not “unduly technical or overly meticulous and literal” (see Saga Holidays Limited v FCT  FCAFC 191; (2006) 156 FCR 256 at ; and Re AGR Joint Venture and FCT  AATA 1870 at ). The approach adopted by the Commissioner is therefore correct."
Waverley Council and FCT  AATA 442 (AAT; Downes J, President, and Frost M; 19 June 2009).
For a copy of the decision, go here