When you use:
NET USER UserName <password> /EXPIRE:<mm/dd/yy> /ADD
to create an account, the expiration date has changed when you view this account in User Manager?
Actually, there is nothing wrong, except that the programmers at Microsoft don't talk to each other, and neither do their managers.
NET USER sets the account expiration to 00:00 on the date you enter.
net user test <password> /expire:12/01/99 /add
net user test
User name test
Account Expires 12/1/1999 00:00
When you view this account in User Manager, it shows the expiration as:
End of 11/30/99
Which is the same date/time:
11/30/99 Midnight = 12/01/99 00:00.