Some time ago I talked to authorize.net about this very thing, and they said a different system was used for address verification outside the US, so there would never usually be a match. I was told if the message came back "no match" in fact, that it was likely they were using a US-issued card fraudulently. I don't know about that. I have just turned off the ability of AVS to decline a transaction. Even for US transactions, I sometimes get "no match" when the billing address is a PO box or the street name is a number. My verification for international transactions is my intuition--what are they buying and so on. It works a lot better than AVS.