Error in characteristic derivation at the level of the invoice item when re

Question

We are implementing the SAP project for just one small private medical Center which includes mainly outpatient cases in different medical Clinics (different departments in the same medical center) .For example: Radiology center/department, cardiology center Obstetrics center and so on.
We have defined each center/department as a different profit center.
Some of departments are subdivided to several medical organizational units; each unit represents a different cost center at the same profit center/department.
A case-based order (internal CO orders relating to a patientu2019s case) is created in the background when the patient is admitted
The same patient can get services from few organizational units (in ISH)/cost centers at the same visit/case and that's why it is important to collect revenue and costs at the same case based order. The revenue is posted to the case base order by using billing in the ISH module and the costs by internal activity allocation.
We have assigned IS-H services to activity types in Controlling; the services transfer to the case based order. CO-relevant services are posted from IS-H to cost centers in CO and within internal activity allocation, allocate them to the case-based order.
For example:
X ray service assigned to Technician minutes activity type.
Each X Ray service takes 20 minutes of  Technician (Qty Cnv Facto=20 MIN)
The service transfer is preformed automatically at final billing.
We have implemented Case Costing Level 2 in order to analyze case costs in CO-PA.
We want to have the ability to derive the profitability analysis characteristics at the level of a line item in the case, for example: we want to define a service or the preformed organizational unit as a characteristic in PA.
We are not sure what the best feasible solution for this requirement is.
We investigated few alternatives: 
1.     We have defined the case based order as real order with a settlement rule to a profitability segment. Revenue and Costs are posted to the cased based order and then settled to the profitability analysis. We eliminated this alternative because we didn't find any way to distribute revenue and case costs to PA between the different "line item characteristics" (for example: different services in the case).
2.     After eliminating the first alternative we tried to change the solution.
We have dealt with revenue and costs separately.
1.     Revenue: In the "configure revenue accounting" We flagged the Post to Prof.Segment checkbox, the patient billing module attempts to determine a profitability segment in CO for each invoice item and to post the revenue to it. The system determines the profitability segment using the characteristics of the patient and case data we defined.
We are using ISH_CHARACTERISTIC_* functions for characteristic derivation but we couldn't derive user defined characteristics which are defined at the level of the invoice item. (For example: billable service in the case or preformed organizational unit for each service.).We didn't succeed to it by using the ISH_CHARACTERISTIC_* functions.
2.     Costs:
We tried to posts case costs (internal activity allocation) directly to profitability analysis, this way we hope to have the ability to derive characteristic of the line item.
We know that when we use transaction: KB21N for internal activity allocation and we define two receivers, internal order and profitability segment- In case the order will be statistical the true posting will be to profitability analysis segment.
Therefore we have defined the case based order as statistical order.
We want to intervene in the automatic creation of account assignment lines by enhancement NHCO0001 IS-H: Create account asgmt. line during CO transfer.
The transfer program creates for CO-relevant services account assignment lines for Assignment rules.
But-We didn't find any way to do it, because the profitability segment object is missing in enhancement NHCO0001.
As an alternative we tried to use User-Exit in the profitability analysis valuation (transaction: ke4u) but also with no success. (Enhancement COPA0002).
Could you Please advice what to do,I didn't succeed in my ideas and investigations.
Thanks
Yael Jacobi
Controlling Consultant

Answer 1

HI Claudius
Thanks for your answer, I will try to discuss it again with my customer to understand weather he really needs/wants a profitability analysis on service level.
I processed also an inquiry within the Service Remote Consulting according , I will let you know their answer as well.
I have additional issue to discuss with you , please let me know wheatear you can help me.
There are internal service sales between different departments in the same medical center. For example: Radiology center/department sells X-rays services for the cardiology center. We need the ability to sell a service to a different department in a different price than to an external payer/customer/insurance provider.
Is it possible to implement profit center transfer prices along with the ISH_CO integration?,
How is it getting along with the posting of internal activity allocation when services transfer to Controlling?
At standard the costs are allocated (by means of internal activity allocation) between profit centers. The responsible cost center (assigned to the performing organization unit) is credited and the case based order (which is assigned to different profit center) is debited.
Is it possible to implement transfer prices in case the performing organizational units are connected to the same profit center? (because some of departments are subdivided to several medical organizational units; and each unit represents a different cost center at the same profit center/department).
Do you recommend defining a different profit center also for each sub-department?
Do you have any other proposed solution for this issue?.
Thanks,
Yael