Personally I've never seen them myself, either. I think you're right that it depends on the premises. If you talk to a white label operator, they will say each set of premises has a different business case for the machine. At some machines you have 200 to 300 transactions per month, but those transactions are valued by those consumers who frequent those premises.
So I have not seen that type of fee structure, but I can't comment across the board, because Interac neither deploys nor operates ABMs.