Posting Logic In The Reconciliation Ledger 
Purpose
You can make a
reconciliation posting at the end of a period or any other time between CO and FI. The SAP R/3 System posts all internal CO postings that apply to all company codes, business areas, or functional areas. It does this in summarized form and posts them to FI.Process Flow
For further reconciliation postings, the system only determines the reconciliation postings delta, and transfers this value to FI.
This prevents CO data from being transferred twice to FI.

The FI document contains two items:
The FI document created can also have more than one item. The system creates the FI document with a totals record from the reconciliation ledger. This totals record does not have to have the same +/- sign in all the amount fields, for example, due to fluctuating exchange rates. In this case, the system splits the document item for the FI document into two items, which have the same +/- sign in all the amount fields.
If the amount of a total record in the reconciliation ledger is greater than the maximum possible amount in the FI component (possible, as the amount fields in CO have more spaces than those in FI), the reconciliation posting splits the CO amounts into lots of FI documents that have sufficiently small amounts.

You make a primary cost posting in company code 0001, and a reposting from company code 0001 to 0002.
Component |
Company Code |
Posting |
Account/Cost Element |
Amount |
FI |
0001 |
Primary |
400.000 |
+500 USD |
CO |
0001 |
Primary |
400.000 |
+500 USD |
CO-FI |
0001 |
No reconciliation necessary |
||
CO |
0001 |
Primary (reposting) |
400.000 |
-300 USD |
CO |
0002 |
Primary (reposting) |
400.000 |
+300 USD |
FI-CO |
0002 |
Reconciliation Posting |
400.000 |
+300 USD |
FI |
0002 |
Offsetting posting in FI |
200.000 1) |
-300 USD |
CO |
0001 |
Secondary |
600.000 |
-200 USD |
CO |
0002 |
Secondary |
600.000 |
+200 USD |
FI-CO |
0002 |
Reconciliation Posting |
210.000 2) |
+200 USD |
FI |
0002 |
Offsetting posting in FI |
215.000 1) |
-200 USD |
The reconciliation posting was made here for company code 0002 only.
Result
The system displays a list of the created documents. You can go to each
line item report in the reconciliation ledger via the individual amounts in this list.During the update run for the reconciliation posting, the system also displays the document numbers of the reconciliation ledger documents that were created. You can go to the corresponding FI document via these document numbers.