You are booking it to the live audience, not the TV audience. During commercial breaks there is still stuff going on at the actual live event such as a promo or a match.
Is there any "Commercial Break" angle? Booking 180 mins of RAW is
I'm sure in something called Media or anything called like this, there is a feature which allow you to change the lenght of the TV Show ( and you can do it even if you are booking a show )