See the sibling reply, the statement led me (probably like you) into thinking that merchants can be charged differently based on every minor aspect of the card,

See the sibling reply, the statement led me (probably like you) into thinking that merchants can be charged differently based on every minor aspect of the card, where they seem to say it's only different depending on the broad classification of the card in that interchange (regular "Visa" vs. "Visa Rewards Signature" for example).