When upgrading or downgrading a membership, ROLLER uses the following formula to calculate the one-off pro-rata amount charged or credited to the customer:
- Unit.cost1 is the unit cost of the membership that is upgraded
- Unit.cost2 is the unit cost of the new membership
- Billing.period.length is the current recurring billing period. For non-recurring passes, the billing period length 1
For recurring memberships, the billing period length is defined as:
A customer wants to upgrade their membership from a $20p/m to a $30p/m membership. If the customer upgrades halfway through a billing cycle - they will have to pro-rata $5 immediately and then begin paying $30p/m upon their next scheduled payment.