Performance issues with Create Accounting - idle times increasing each monthly AP close

Performance issues with Create Accounting - idle times increasing each monthly AP close.  (Oracle Payables version 12.0.1)

On average, it takes the Create Accounting process 2 hours and 45 minutes to complete; we would expect this process to take no longer than 30 minutes. Each monthly AP close, create accounting idles times increase, with most idle time spend in receipt accruals. We have tried purging historic AP records in dvl, but very few (<2,000) records met the purge criteria. Wondering if other users have experienced this loss of efficiency over time and some solutions to look into outside the purging of historic records.