You're in luck. There are two ways to adjust the volume levels of commercials. The first is VOL -. The second is Mute.
Sorry, but there is currently no way to automatically decrease the volume levels of commercials. Some TV's have AVL (Auto Volume Leveling), but I haven't found this feature to be very helpful. The loudest commercials I am aware of are the ads running in the background while navigating the On Demand menus. Is this what you are referring to, or is it a particular channel?
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