Media Center and sleep

What is the proper operation of the system when media centre is playing live
TV? What happens now is that the screen saver will come on as set to do
after 10 minutes then the monitors will go into standby mode after 30
minutes, but the computer will never sleep after 60 minutes as it is supposed
to do.

Now, perhaps this is as designed during live TV, but if it is, wouldn't it
also be by design for it to override the screen saver and turning off the
monitor settings so as not to interrrupt the TV broadcast?

In the power settings I do have it set to allow the computer to sleep while
sharing media.

So, what is considered normal sleep operation in this case? When media
centre is not running the computer sleeps at the 60 minute mark as it is
supposed to.

Thanks.

Bart