"use imported mp3 quality" option is missing

Hi there,
This is a very specific problem and I hope someone else has experienced it and found the solution!
I’m working on a project with multiple pages, each one is a swf file that gets loaded into another “player” swf file. My goal is to streamline production, so I want to stick with default settings as much as possible. So, the default audio settings are 16kbps mono. But for imported mp3s, the default is to “use imported mp3 quality” (which is available as a checkbox when you open the sound properties window by right clicking the sound in the library and choosing Properties). That’s all fine, and works the way I want it to.
My problem is, that some of the mp3 files that are provided to me don’t have the “use imported mp3 quality” checkbox even available, and so they are set to default quality, which means they get the document-wide 16kbps setting and end up sounding awful.
I’m working with a professional audio technician, so I’m trying to find out what the difference is between one mp3 and another. It’s like Flash can’t read the information out of one file, so it can’t use the imported mp3 quality because it doesn’t know it.
I think the difference is in the way the mp3s were created by the audio person, but she swears they were made the same way. Is there a setting when making mp3s from an audio program(like bitrate for example) that could be affecting Flash’s ability to extract that information from the file? I know that I can simply change the settings for those audios, but that could get awfully old after the 300th swf export…which is why I want it to work with default settings. Publish profiles seem extremely clunky, and not very time-saving, unless I’m missing something…
Whew…that was a long one…Thank you for any tips you guys may have.