In the Accrual Engine, the system can be customized to perform either full or delta postings. 

When full postings are configured: 

• An inverse posting is automatically created at the start of the current period. 

• This inverse posting reverses the accruals posted in previous periods. 

• After the reversal, the new accrual amount for the current period is posted. 

As a result, a manual reversal of accrual postings is not required: 

• If full postings are used, the automatic inverse posting takes care of the reversal. 

• If delta postings are used, manual reversal is not applicable, as only the change (delta) is posted. 

The setting for full or delta posting is maintained in the IMG activity: 
Define Accrual Item Types 
(Viewcluster VC_TACE_ITEMTY) 

What Is an Inverse Posting? 

• An inverse posting is not a true reversal; instead: 

• The last accrual posting is selected. 

• The signs of the amounts are reversed (positive becomes negative and vice versa). 

• A new posting is created using these inverted amounts. 

• No reversal reason is required. 

How the Inverse Posting Is Determined: 

1. Balance Calculation: 

• The accrual object balance is determined by aggregating all previous accrual postings to the accrual account. 
• This includes G/L balance carryforward values (via transaction FAGLGVTR). 
• However, starting from Release 1909 FPS1 and 1809 SP3 (Note 2838716), the balance carryforward is no longer required. 
• Instead, balances are aggregated across all available fiscal years directly by the Accrual Engine.

 2. Selection of Previous Postings: 

• Previous accrual postings from earlier periods or fiscal years are selected. 
• If an uninverted posting is found whose amount matches the current balance, that posting is inverted. 
• The same G/L accounts and line items are reused, but the amounts are inverted. 

• The account assignment is newly derived for technical reasons. 

3. If No Matching Posting Is Found: 

• A new inverse posting is generated from scratch: 

• G/L accounts, posting schema, and the number of line items are derived as for a normal accrual posting. 
• Only the signs of the amounts are inverted.

See more technical details about the below topic>

No reversal at the beginning of the next month in ACEPOSTINGRUN – accrual engine 

Reversal of Accrual Postings: Single Accrual Object Postings

Reversal of periodic accrual posting