When an end-user changes their subscription plan from their account page on the end-user dashboard, Uscreen calculates their current balance and then applies it towards the daily cost of the new subscription price.
Whether the former and new subscription plans are monthly, yearly, or some other duration, Uscreen breaks the cost of that down into a daily price. In essence, all subscription plans get broken down into a monthly rate and then divided by the average days in a calendar month (approximately 30.41 days).
From there, Uscreen will compare the current credit of the user against the new daily cost and will invoice the end-user once their current balance is exhausted by the new daily rate.
This in-system crediting only applies when the customer changes their subscription plan through the end-user dashboard. If an Admin changes the subscription plan for an end-users via the Admin area on the end-user's behalf, the Admin will need to make sure to adjust the next billing date accordingly, otherwise the end-user may be charged much sooner than they should be.