Gratuity based on Basic Salary

Hi Experts,

My client in UAE want to give gatuity based on following scenario

less than 1 year --> No Benefit

1 full year --> 21 days of Basic salary

From 1 year & 1day to 5 years --> 30 days of Basic salary

From 5 year and 1 day to 10 years --> 45 days of Basic Salary

Please let me know how I proceed for above scenario.

If we need custom PCR's for above scenarios, then kindly help as my knowledge is very restricted.

Regards

S.Ravi