The Time-Off Accrual Report calculates the Hours Available based on how the “Base Benefits Availability on” field value in Payroll Options. To review, Launch Payroll, Setup, Payroll Options and select Time-Off tab.

• If 'Base Time-Off Availability on" field it’s set to L for Limit, the Available Hours on the Benefit Accrual Report use this formula:
  
  (Annual Limit + Carry Over Hours) - Hours Used. The Available Hours are multiplied by the employee's Pay Rate to calculate the Accrual Balance. When basing hours available on annual limits, YTD Accrual Hours are ignored.

• If “Base Time-Off Availability on” field is A for Accrual, the Available Hours use this formula:
  
  (Carry Over Hours + Hours Accrued) - Hours Used. The Available Hours are then multiplied by the employee's Pay Rate to get the Accrual Balance.

DocLink: Time Off doesn’t calculate or accrue in Payroll