clarifications regarding Cost centers

Dear all,

we have an assginment of say cost center C1 to service org. I mean the assignment in Master Data > org mgmt > cross appln settings look like

SrvOrg1 + * + * -

> C1.

Now in my service order if an employee is working in whose personal master in HR we have maintained cost centre C2, where is the postings happen. Under what condition would C1 be picked and when C2 is going to be picked?

Please help.

Thanks and Regards,

Kiran C