In different organizations, the pay cycle varies. Some companies consider it from the 16th of the previous month to the 15th of the current month, while others use from the 21st to the 20th (as in your case). There are also those who calculate it from the 1st to the last day of the month. In the last scenario, there are no issues. However, in the previous cases, the employee is assumed to be present for the next 15/16 or 10/11 days based on the pay cycle system. In the event of any leave without pay (LWP), the period is adjusted when computing the salary for the following month. For instance, for the month of May, absenteeism will be counted from the 16th of April/21st of April to the 15th of May/20th of May, as the case may be. If an employee takes LWP, the days of absence will be deducted from the salary for the next month.
I hope this explanation clarifies things for you.
Regards,
Arun Jain
HR Personnel
NCL, Coal India Ltd.