They are two Accrual methods
1 Accrue on Recepit
2 Accre at period end

Accre on receipt means that when a receipt is saved, 
accrual transactions are immeditely recorded and sent to gl 
interface. This is also known as "online" accruals.
Accrue at periond end means that when a receipt is saved, 
the accrual transactions are not immediately recorded and 
sent to gl; instead the accounting entries are generated 
and sent at the end of the month by running the Receipt 
Accrual-Period End process