In most cases, that’s a good thing. The only person worried if their commercial is loud enough, is the client. Everyone else is saying, “why are all the F#$*ing commercials so F&*#ing LOUD!! —while reaching for the mute button. Most television shows have dynamics—some parts are louder than others. Makes for good drama. Most TV commercials, as dictated by the ALL-KNOWING AD WIZARD, have one dynamic—as loud as freakin’ possible! Makes for good annoyance, or as previously mentioned, frantic scrambling for the mute button. This wasn’t a problem before the advent of digital TV. In the good old days of analog, there wasn’t the dynamic range there is now.

http://www.crtc.gc.ca/eng/publications/reports/rp110318.htm

Did you read the whole thing? I thought not. But enough to realize there are several contributing factors involved in determining what volume a commercial is played at any given time, on any given station. So next time a client calls you in the middle of the night saying, “I just heard my f*#$ing commercial on the Food Network and it wasn’t as loud as the one right f%#*ing before it—tell them, “Wow, didn’t we get lucky!”