Grantee Management - Billing - RRB on Liabilities - need an enhancement ?

Question

It seems like there is no way to configure RRB on Liabiltiies without an enhancement.
Scenario - Grant Billing where it may be on acccrals, liabilities or payments - one Billing Rule for each.  No problem with RRB for Accruals (AP Invoices, GR/IR - using VT = 99) or RRB for Payments (using VT = 57).  And no issue if unvaluated Goods Receipts (since invoice is accrual point with VT = 99).
The problem is with the "Valuated GR" scenario, which is perfectly valid for Public Sector, and when grant billing needs to e on the Invoice, not the Goods eceipt.   There are several points to contend with :
1.  GR/IR accrual needs to be ignored - so these account postings can be put in a GM Value Type Zn which is not billed for Liabilities  (this has Debit to VT = 99 and Credit to VT = 54).
2.  Invoice posting - Billing on VT = 54 to the Vendor (Liability Account) - this is a credit and will be billed with the wrong sign unless the VT = 54 is defined as "Payments" and so the SAP hard-coded program will multiply the credit entry by -1 and bill correctly.
Great so far.  But then :
3.  When the invoice is paid, we get the credit to cash outwards clearing and debit to Vendor (clearing the invoice) - and this debit it will be included in the RRB selection.
So I exepct an enhancement is needed to that for the RRB on Liabilities so the Doc Type can be checked.  
-   For an vendor invoice, the sign can be flipped (otional, so VT = 54 can be defined as a Actual and not a Payment).
-   For the Payment document the VT = 54 can be ignored.   
Note : none of the standard config is FI Doc Type related.
Several of my colleagues have come to the same conclusion - that an enhancement is needed.  Have I missed something, or has SAP missed something ?

Answer 1

Hi,
I have heard from other customers wanting to bill at Invoice receipt.
This was their approach:
At the time of posting the GR, they did not have two real postings, instead, they had 99 (real expense), Zn Statistical GR/IR.
In the Invoice receipt, you would then have a Zn (stat) and a 54 to liabilities (AP). You can code a BAdi to make Zn real only in the IR.
Then, they had a billing rule to pick value types 99 and Zn only.
it is true that they were actually using a badi, but I think it's simpler to handle a badi based on value types rather than document type.
Maybe this could fit your scenario too?
Kind regards
Mar