I agree with Alan, that this is a function of the Operating system to ensure the time is correct. However, having said that, I have that function disabled on my system, preferring to do it myself periodically.
But, the time sync should be talking in adjusting seconds or minutes and neither of which would account for the type of discrepancy to cause WSC to say it is out of date, typically 7 days. Mostly this is either a CMOS battery problem or someone has used the clock to check a date in the future or past and forgotten to set it back.
I also check the clock frequently, hover the mouse over it and you will see the date as well as the time, this can pre-empt any potential sync problem.
Another thing, I don't really want avast to acquire another function that would either it first checks for a connection (ping) or actually establish a connection (god forbid, no auto connections {dial-up}). We have numerous posts in the forums complaining that avast is connecting to the internet and this would add to it.
You would also have to build in a number to atomic clocks check in turn, to cater for unable to connect or sync. Next if the users sees that the colck/date is incorrect then avast would be a candidate for possible blame.
Sorry, but as I said I feel this is an OS or user function.
I use a little program called about time that can be used as a stand alone application to be launched by the user, as a dial-up user I have a real hatred to any program that tries to automatically connect to the internet.