ADB questions and ADB Aggregate Amount not calculating correctly

PeopleBooks indicates, “ADB uses either the incremental method or the ad hoc method to calculate average balances.”  Should we get the same results if we use one method or the other? Specifically, how do we use incremental method or the ad hoc method?  PeopleBooks indicates, “by default the ADB Calculation process uses the ad hoc method to calculate average balances.  In order to use the incremental calculation, you must define the ADB definitions and period type on the General Ledger Definition – Incremental Calculation Method page” To use the Ad Hoc method do I check the ‘Adhoc’ box on the ADB Process Request page? If I leave the box uncheck will the process use the incremental method?