Hi Leah,
Saverance Pay is base on ‘Basic Wage’
Basic wage is mean the money that the employer and the employee agree to work of the employee. In a normal working day and time, such as salaries, wages, daily living. Value, location, etc.
But as your concern to wording that is mean income non fix pay to employee for benefit , for allowance. It pay tempolary. It isn’t basic wage.