Exchange 2007 shows different mailbox size than Outlook 2003

[RyeGuy]

I have a few users today who's mailboxes are on a new Exchange 2007 server. We just changed the "storage quota" for all mailbox's. One user, for example, hit his mailbox limit of (50MB) and as the system is supposed to, it restricted his ability to send giving him the Mailbox Cleanup window. He cleaned his mailbox up reducing the size to 6 MB (according to Outlook). He is still unable to send. I looked at the properties of his mailbox in Exchange and it shows that its still at 50 MB. His mailbox retention is set to 14 days which to my knowledge doesn't affect his storage limits, but to be sure I purged all items in retention. Size still shows as 50 MB. Any ideas? I've confirmed that most users are showing a different size in Outlook than Exchange. Today is the first day this has been looked at. I've heard that database maintenance that runs at night will clean that up, but that would mean that whenever a user cleans up their mailbox they won't see the benefit until the next day. I can't imagine that is the case. If anyone has any suggestions please let me know.

-Ryan