Authorization code issues

One of the merchant vendors that helps in managing our payments for our company recently brought to our attention that several sets of orders placed through our Woocommerce website have, for some reason, been submitted with only one authorization code. That said, when we spoke to our website’s payment gateway, Authorize.net, they informed us that each order did in fact have it’s own separate authorization code. We understand that each order must have it’s own individual authorization code as provided by the credit card holder’s bank. Why would Woocommerce be submitting only one authorization code per set of several orders ?