Transfert to COPA based on turnover

Hello,

I have this problem.

We are in a same Company.

I would like to have a CO transfert between CO-OM and CO-PA based on the turnover. At this moment you think, it's simple by using assesment with cost center or by using internal order. I'm agree with you except the cost I have to transfert from CO-OM is a percent of the turnover (in CO-PA)

Thanks for help