Intercompany Credit Memo functionallity

Hi

I have this scenario in R12:

At Expenditgure Inquiry, I did a Transfer to an IC transaction already Intercompany billing Processed let say under Draft #10, Total Invoice Balance Due=900. Due to the Adjustment done a Credit Memo and an Invoice was created let say Draft 20 -100 and a new invoice Draft 21 100. When the XI strreamline process is completed, the Original Invoice Balance Due is 800 and the Credit Memo Balance Due is 0.00.  Why iis it applied automatically the  Credit Memo (Draft 20) against the original Invoice (Draft 10)?  We did not see that behavior in R11, is there a setup or profile?