SAP Netweaver Enterprise Controlling

Symptom
It is not clear why different Profitability segment numbers (PAOBJNR) are created in standard SD process “sales order -> delivery -> invoice” when account based and costing based profitability are both active.
The customer release is 47 (SAPKH47016) or higher.
Other terms
MEINH, MEINS, CE4XXXX, CE4XXXX_ACCT, CE4, CE4_ACCT, profitability segment, PAOBJNR, account-based, costing-based, KEQ3
Reason and Prerequisites
The PAOBJNR in account based CO-PA line item will always be different from that in costing based line item. This is because the unit of measure (MEINH) is always part of PAOBJNR in account based but not in costing based CO-PA. Also the KEQ3 settings could differ for account based and costing based CO-PA.
Solution
If both account-based and costing-based CO-PA are active the creation of profitability segment numbers during the SD process flow happens as follows
1.) Creation of sales order:
The profitability segment is determined on the sales order if incoming sales orders is active (tcode KEKF) or account-based profitability analysis is active or it is make-to-order production.
When the sales order is created derivation gets called and a CE4XXXX_ACCT-PAOBJNR N1 with field MEINH filled is determined. Field MEINH must be filled because the account-based segment number for the COEP line item at time of goods issue is determined out of the sales order’s segment number. VBAP-PAOBJNR will also be N1. The CE4KEY N2 of PAOBJNR N1 from CE4XXXX_ACCT is a segment number in CE4XXXX and gets created from N1 based on KEQ3 settings for costing based COPA but with initial MEINH value (as of note 657844).
2.) Creation of delivery and goods issue:
The sales order’s segment number N1 is taken over into the delivery and also used for posting goods issue. If there is no redetermination of the segment number (that can sometimes happen during posting goods issue) the corresponding MM and FI documents get N1 as MSEG-PAOBJNR and BSEG-PAOBJNR respectively.
Moreover an account-based CE4XXXX-PAOBJNR N3 is determined out of the sales order’s segment number for creation of the account based COEP line item for goods issue (field COEP-OBJNR).
3.) Creation of the invoice:
The sales order’s segment number is also taken over into the billing document i.e. VBRP-PAOBJNR = N1. The account-based COEP line item for the billing uses the account-based CE4XXXX-PAOBJNR from goods issue i.e. N3 whereas the costing-based line item for the billing uses the CE4XXXX-PAOBJNR = N2 created during the sales order creation. BSEG-PAOBJNR = N1 for the FI document created when the invoice is released to accounting.

ADDITIONAL PAOBJNR:
If only account-based CO-PA is active CO-PA derivation will happen only once at the time of creation of sales order.
If additionally costing-based CO-PA is active derivation will happen twice; once at the time of sales order creation and second at the time of COPA line item creation during billing.
Second derivation (during creation of costing-based line item) sometimes has a different result compared with the derivation executed at time of creation of sales order. In rare cases it could happen that the master data or derivation logic is changed between the time the sales order is created and the invoice is released to accounting. This can result in a new PAOBJNR N4. This could also happen if the derivation logic for certain characteristics is such that they will be only derived during billing.

CONCLUSION:
CE4XXXX_ACCT-PAOBJNR = VBAP-PAOBJNR = LIPS-PAOBJNR = MSEG-PAOBJNR = BSEG-PAOBJNR = COEP-PAOBJNR = VBRP-PAOBJNR = N1
CE4XXXX-PAOBJNR (acct based) = COEP-OBJNR = N3
CE4XXXX-PAOBJNR (cost based) = CE1XXXX-PAOBJNR = N2
CE4XXXX-PAOBJNR (cost based) = CE1XXXX-PAOBJNR = N4 (rarely happens)
Three segment numbers N1, N2 and N3 created normally. In some rare cases N4 will be created as explained above.
In general there is no link between the two profitability segment numbers N3 and N2 of the account-based and the costing-based CO-PA line items.