Hi,
Mr.Mozzam already shared valid points, I would like to add one more point here
Normally customer credit limits are managed in credit control area and we will assign company code to credit control area
whenever sales takes place,sales organisation will determine respective assigned company code.
from company code to credit control are will determined by SAP,its a standard behavior.
by using the credit control area,SAP knows which credit management rules apply to the sales,and what credit limit the customer has for the sale.
Regards,
Krishna.