Can you clarify the form no (i.e, i,j,k,l), which you are naming as gratuity register.
As per gratuity act, it will be eligible for the employees whoever is completing 5 years of service or 240 days in the 5th year. Only their details need to be filled, if at all you are maintaining a record of gratuity.
For accounting purpose, every year auditors used to show that as a liability for next year.