Abstract: Online transaction processing over a communication network involves receiving a transaction input comprising an authorization request message for a transaction conducted over a communication network between a consumer and a merchant using a portable consumer device having a memory, wherein the authorization request message contains data comprising a transaction total amount for the transaction and additional information not stored in the memory of the portable consumer device and related to the transaction. Issuer authorization processing is performed in response to the authorization request message data, and a decision output is produced in response to the transaction input and the issuer authorization processing. Thus, a decision output is produced in an efficient manner using additional information for the issuer authorization processing, and the additional information reduces the likelihood of declining a transaction that should otherwise be authorized.