well zip code thing seems strange because only American companies use zip code when they charge a credit card. But for foreign transaction no other country use zip codes or anything else.
International credit card transactions are done purely the credit card number the expiry date and the "secret" three digits on the back... Secure. Lol
that's great if it works to the debit card. But for a credit card probably will charge you cash advance fee but that would be very high interest rate like 20% maybe....
well I live here 5 years and yes the yellow machine may give you more but the others even 25k often you have to go down to 20K from foreign card. This is mostly in Bangkok.