JosephParticipant
The typical mechiras chometz transaction between the Rov and mispallel takes about three minutes. You pick up an object to make a kinyan and you then write down your name and address on the Rov’s piece of paper.
Based on the aforementioned, Hadorah’s presumed rate should equal to $25-$35.
Usually when someone has an hourly rate, it means the minimum is for an hour. The rest can either be a full second hour etc or a partial hour. So i think your math is off , assuming mechiras chometz should be done by a hourly contract price.