Hi Iwan,
What I mean in my previous thread is that you need to mention cost component structure before you activate Object Currency in Version Maintenance.
I referred to OKTZ to give a clue that list of cost component structures listed in this transaction which you might be knowing already.
Referring to the note 999985 - It speak about some product bug with respect to calculation and which need to be implement based on SAP Version which you are using.
Please let us know what is the issue you are facing with activation of this function, so that more inputs can be provided.
Regards,
Santosh Varanasi