To update the thread: there was an issue that prevented AdWords API
usage information from being updated following the scheduled downtime
on March 14. For a few days after there was a backlog of usage info,
and both the display in the AdWords web interface and the count
returned via the InfoService was out of date. The engineering team
believes that this issue is resolved now, and that the underlying
circumstances leading to it should not recur.
They did identify a window of about an hour on March 14 for which
they were not able to retrieve usage information, and any calls made
during that window of time will not incur any charges (nor will they
be reflected in the InfoService or the web interface's usage count).
However, this window took place during the scheduled downtime, so
there should have been only a small amount of traffic that got through
during that time.
Apologies for any inconvenience this has caused.
-Jeff Posnick, AdWords API Team