Why FCCS is not able to calculate the minority interest in chain holding ownership structure?

Below is my ownership structure -

A holds 90% of B and B holds 80% of C.

Here, the effective own % of A against C is - 80*90% = 72%

MI% of A against C = 28%

But in FCCS, the numbers are calculated from a different angle without considering the Own % -

MI of B against C = 20%

MI of A against B = 10%

So FCCS is calculating the MI for A against C as - 10*20% = 2%.

How can this be addressed by configurable consolidation rules?