SLA Derivation Rules - Difference between FA_Default_Account and FA_Default_Offset_Account Rules

I have a requirement to to Create JE's in Detail (Using the Company, Cost Center, and all other segments except Account from Assignment Record) for all Accounts. In most of the Oracle Delivered rules the Flexfield_Segment_Code for the "All" segments uses the "FA_Default_Account" Derivation Rule. I know that when I create custom rules I should change this to "FA_Expense_Account" in order to get the desired results. On a number of the Oracle delivered setups there are other Derivation Rules used instead of "FA_Default_Account". These include FA_Default_Offset_Account, FA_Counter_Account, FA_Counter_Offset_Account, FA_Cat_CIP_Cost_Clearing, & FA_Cat_Cost_Clearing.