It makes a great story: Indie filmmaker's expose baring the inconsistencies of movie ratings prompts the Motion Picture Association of America (MPAA) to revamp a system softer on violence than sex.

For years, films in which a woman is carved up with a chainsaw have merited an R rating while those in which a woman has consensual sex have gotten branded NC-17. And, for just as many years, critics have demanded: What kind of message does this send to the kids the ratings system presumably means to protect?

There will be some changes made, MPAA honcho Dan Glickman announced Monday at the Sundance Film Festival, where Kirby Dick's entertaining MPAA-trashing This Film Is Not Yet Rated premiered a year ago.

According to Glickman, they were in the works before Dick's film was released. Yet regardless of whether we have Dick to thank that the people rating movies for children will now actually have to be parents of children 5 to 18, any moves to open the curtains on the MPAA's top-secret system are welcome. But do the moves have any muscle?

Glickman and MPAA spokesman Kori Bernards emphasize "the need to make the process more transparent." I applaud their proposal to improve information about movies, their ratings - and their raters! - on its Web site (www.mpaa.org).

And I'm thrilled that the organization, which lobbies on behalf of the movie studios, belatedly acknowledges its bias against independent filmmakers. Rule changes will now give indies the opportunity to appeal a rating decision by referencing similar scenes in other films.

Speaking as both a critic and a mom, none of these proposed changes speaks to my fundamental problems with the MPAA Classification and Rating Administration (CARA for short).

How does the coarse, bodily-fluid-awash Austin Powers rate the PG-13 designation while the tender (if F-word-laced) Four Weddings and a Funeral gets branded R?

How does the unsparing, bone-crunching, big-bang violence of Armageddon rate a PG-13, and that humanist study of sexual violence Boys Don't Cry gets an NC-17 that fights to be appealed down to an R?

Year after year, the MPAA rates juvenile sex humor as more acceptable for American youth than sexual tenderness. Year after year, its ratings suggest that gun and war violence are more suitable for consumption by the nation's teenagers than consensual sex.

Now, different aspects of films push different parental buttons. Some, like me, want to protect our spawn from violent content; others are more sensitive to sex. Every parent I know, liberal or conservative, hates gratuitous profanity. (Based on its title alone, I'm still scratching my head that Meet the Fockers got a PG-13.)

Movie for movie, the British Board of Film Classification (www.bbfc.co.uk) does a far more balanced job than the MPAA in rating sex, violence and profanity. (In the U.K., Four Weddings and a Funeral was rated "15" - OKd for those 15 and older - likewise Armageddon; Pulp Fiction got the "18" stamp, meaning you have to be that age to be admitted.) Perhaps the BBFC is more internally consistent because it has fewer external pressures.

Unlike the BBFC, which has one mission - to provide consistent information to consumers of movies and videos - the MPAA serves two masters. It is a trade and lobbying agency for the movie studios in Washington and the provider of ratings guidelines for consumers.

Is it a conflict of interest when one arm of an organization represents a studio that wants a favorable rating that the organization's other arm might confer? With their PG-13 ratings, Spider-Man and X-Men would suggest so.

MPPA's Bernards says there will be more changes announced in March. I hope they will address some of these concerns.

More important, I hope they close what is currently a gaping loophole in the application of the MPAA ratings system. In 1999, after the Federal Trade Commission found that Hollywood routinely marketed films rated R (restricted to those over 17 unless accompanied by a parent), the MPAA pledged that the studios it represented would no longer advertise this fare to teenagers.

Alas, this promise did not address violent films rated PG-13 (parents strongly cautioned, some material inappropriate for those under 13). So why is your 10-year-old watching Nickelodeon and seeing ads for Spider-Man and X-Men and other PG-13-rated films?

Contact movie critic Carrie Rickey at 215 854-5402 or crickey@phillynews.com. Read her recent work at http://go.philly.com/

carrierickey.