I might be a tad out of date and Mr Olney might know more, but credit card fees were 2% and Am Ex 2.5% as charged by the banks. The higher Am Ex fee discourages retailers form making this card available as a payment option as it bites into their margins. I have an Am Ex cash back card and I am quite limited where I can use it due to theses fees charged by the card issuer.
Arann's charges seem excessive compared to what they pay back to the card issuer?