Proportional amount (Pro rata)
Pro rata is the amount billed to the subscriber if the subscription starts on a day other than the billing date set by the seller. When creating a subscription, the seller can decide whether or not to offer this option.
Below we show a flow of how the proportional collection of payments works.
To define a pro rata for subscriptions payments, send a POST to the /preapproval_plan endpoint with the parameters
billing_day_proportional and execute the request. The first parameter accepts values from 1 (one) to 28 (twenty-eight) and must contain the day of the month in which the charge will be made. The second in turn must be sent with the value