Fund Mgt in Marketing- extra fund usage gets created after running "Actual download from ERP"

Hello,    

I have created a campaign of type Spend Association in SAP CRM Marketing.

I understand the fund usage creation happens via expense mapping to the selected spend types.

Since i selected only one spend type which is mapped to a single expense type, one fund usage was created which is correct.

I then generated a PR, PO out of this campaign in the connected R/3 system.

But after running the report " Actual download form ERP", I see one more fund usage getting created and it also has an expense type "Advertising Cost" mapped to it.

So form where does this come from?

Can any one explain?

Regards,Divya