A conversation I had which I still don't understand

I must be missing something

Baffled, by Terry Freedman.jpg

This is a phone conversation I had with a cab company. We’d reached the stage where I’d established where I was and my required destination.

Me: How much will this journey cost?

Cab company: Would you like to pay £5 or £11?

Me: What's the difference?

Cab company: £6

Me: Thank you, yes, I worked that out. What's the difference in…