Keep in mind that one of those letterboxes could have come from the production company that made the commercial. There are about 92 different possible reasons for this -- ranging from the whim of the art director on the project to the fact that they needed one duplication format to cover all their airbuys.
Active Format Description can help, but it's not foolproof, as some spots are grouped together by organizations outside the station, and are aired as a "package" rather than individually. More here:
http://en.wikipedia.org/wiki/Active_Format_Description
The only way broadcasters will fix stuff like this is for comments to wind up in their FCC public comment file at the station.
And when you're doing a program, it sucks to have to second-guess how your show is going to be presented. Making things "center-cut compatible" eliminates almost 1/3 of the screen area, from a program-critical content standpoint.
Chip