Mixed costing over plants

Question

Hallo,
I want to use mixed costing over plants.
The same material is produced in plant 200 and in plant 210. Both plants are part is the same company. For US-GAAP reasons those materials have to have the same standard price for valuation of the stock and the goods movement.
So, I want to calculate a mixed costing of 60% from plant 200 and 40°% from plant 210.
What did I do :
1. Solution using special procurement type for costing.
First, none of the plants have a special procurement type for costing.
Plant 200 has a procurement alternative (production 60% & stock transfer from 210 40%). I cost for plant 200 giving me a perfect mixed cost.
Then I set the special procurement type for costing in plant 210 to C2 indicating to get the cost price from plant 200.
Calculating this cost price also is OK. But as soon as I save this cost price, the CK13N reports of plant 200 and plant 210 are incorrect because they allow an unending drill-down :
Plant 200 = 60% of Plant 200 + 40% of Plant 210 = Plant 200 = 60% of Plant 200 + 40% of Plant 210 = Plant 200 .....
2. Solution using a procurement alternative per plant.
Here, I do not use a special procurement for costing anymore.
I define procurement alternatives as follows :
Plant 200
   Producing in 200                  60%
   Stock transfer from 210         40%
Plant 210
   Producing in 210                  40%
   Stock transfer from 200         60%
Costing version 1 is linked to those mixing ratios.
First I calculate a pure plant cost price with a costing variant V1 and costing version 2.
Result :
A pure plant cost estimate for plant 200 & a pure plant cost estimate for plant 210.
The I calculate the mixed costing for both plants with costing variant V2 and costing version 1.
Costing variant V2 has a transfer control : cross plant - get "other prices" within the fiscal year, from costing variant V1 and costing version 2.
When I calculate this mixed costing with CK11N, everything goes perfect. I get a mixed cost price in plant 200 and exactly the same in plant 210.
But, when I use CK40N, the intermediate calculations are written to the table KEKO and are used in the calculation of the mixed costing.
This is the result :
Plant 200 = 60% of plant 200 with cost price of pure plant 200
                  40% of plant 210 with mixed cost price of plant 210
Plant 210 = 40% of plant 210 with cost price of pure plant 210
                  60% of plant 200 with mixed cost price of plant 200
Result, I get different and incorrect mixed prices in both plants.
Who can help me. Since this seems to be a US-GAAP requirement, I cannot imagine that I am the only one facing this problem.
Any help will be much appreciated.
Kind regards.
Franciska Brys.

Answer 1

In solution 1, I had a procurement alternative and mixing ration in plant 200 and a special procurement type for costing in plant 210.
Before calculating the mixed costing in plant 200 I had to eliminate the spec.proc.type for costing in plant 210 otherwise, the calculation got into a loop.
Without the spc.proc.type in plant 210, I got a correct mixed costing in plant 200.
Then I enter the spec.proc. type for costing again in plant 210 and calculate the cost price. This copies the mixed costing from plant 200. So far, OK.
But as soon as I save this cost estimate in plant 210, the reports in CK11N or CK13N get incorrect for the first calculation made for plant 0210 while costing in plant 0200 is overwritten by this result. Now the report gets into a loop and you can drill down endlessly.