you may end up with a difference of 1 day whenever the php.ini on your server and your Joomla! configuration are not in the same time zone (depending on how far away they are apart and your time of the day, you will end up with 1 day difference).
Simplify Your Web is not affiliated with or endorsed by The Joomla! Project™ or Open Source Matters. The Joomla!® name and logo is used under a limited license granted by Open Source Matters the trademark holder in the United States and other countries.