CBA does a credit check - once Why would merchants swap is more...

CBA does a credit check - once

Why would merchants swap is more the question to ask? I have heard bigger merchants pay 1.3% for Big 4 bank CCs, 1.8% list. I hope somebody can say what it actually is for bigger players such as MYR, PMV group etc, or what the average merchant fee is. APT internationally is about 3.9% on ave, not counting late fees.