Possible? Yes. Good? I’m not so sure… If there is a problem in my computer, I need its time and date checked and not a server one. Maybe avast could compare the time and date between the computer and the time server and alert the user.

Why does Microsoft offer a non-reliable service? A lot of free tools do the synchronization very well.
Suggestion: http://www.alfaclock.com/ or http://www.mytoolpad.com/open/timesync/servers.php