Every country supported by SmoothPay has different rules regarding leave entitlements. The installer provided for each country implements those rules correctly.
However, it's quite common for data to be brought into SmoothPay from systems that are non-compliant or where an alternative method has been adopted to satisfy requirements.
Our Leave Management Guide covers setting up automatic leave accruals, correcting and consuming leave as well as providing an overview of rules used in each country.