The PIN on the new CBA Amex cards works in CBA ATMs (not that surprising).
The problem is that I assumed that the card's account linkages would be the same. My savings account is linked to my CBA Plat MC, but I tried my CBA Plat Amex to see if it also worked by entering my PIN and choosing savings. I got my $200 cash out, but then checked netbank the next day and it had been treated as a cash advance. Rang the CBA call centre - got one of their very friendly customer assistance people, but she could only refund the cash advance fee. They can't change the order payments are processed to an account, so I am now stuck with cash advance interest accruing until I get the balance down to $0 - unlikely if I'm taking advantage of the promo points between now and Christmas

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Really, CBAs ATMs shouldn't accept withdrawals using the Amex card using the 'savings' account option if it isn't actually the savings account the $$$ come out of - an error message 'that account is not available using this card' would be much better form. Dodgy or lazy programming of both their ATMs and their payments processing systems if you ask me.