costing hierarchy (need cost centre from assignment!)

Hi,  All
I have cost centre on assignment which differ from organization cost centre.
After costing calculations I see what one element gives organization cost centre instead of assignment cost centre.
How can I correct it?

As I know cost from assignment must have higher priority than cost from organization. But it doesn't work..

In Element link I define Costable type as "Fixed costed"
and in Balancing--Cost allocations "Profit/Cost centre" is empty.

Please, give me some advises, How can I resolve the problem.
Thanks