The amount of the surcharge as a percentage. The percentage is provided as a string representing the decimal equivalent of the percentage. For example, "0.7" corresponds to a 7% surcharge. Exactly one of rate or amount_money should be set.
The amount of the surcharge as a Money object. Exactly one of rate or amount_money should be set.
Indicates the source of the surcharge. For example, if it was applied as an automatic gratuity for a large group.