AmEx online services have always been like this, the site is nowehere near the elsuive five 9's for uptime

The problem about account transactions and validity at statement cutoff date is a problem they have known about for over 2 years, they are trying to fix it.....

In answer to the 'how do they get away with this' question; simple, they put 'This is not a billing statement' across the top of the screen, and you are viewing unbilled charges. Until the statement is 'cut', and sent out do the charges actually 'stick' to your account.

Thanks,
Richard