When an end date is set for a user, the application automatically accrues the amount it has to accrue in the next accrual date, even if the user has only worked for 1 day in the next accrual period. 
Accruals are usually set for end of the period, so that a user earns the accrued timeoff. Hence, when the end date is set, the application automatically accrues for the completed period even if the user has worked for only one day in the new period.
* If prorating is set, the application would accrue only the fraction of the accrual amount.
* If prorating is not set, the application accrues the whole amount and adds it to the balance.
Add a new policy with the previous balance as the new balance, and set it with no accruals.