Running Time?

Just taped FAT CITY from a TCM showing and it clocked in not at 100 min. But 97, which is the same as the DVD. Therefore my questions are
1. What has happened to the original 100 min. version?
2. What was cut out of the subsequent DVD and TV versions and why?
3. Why doesn’t the IMDB site allow updates on running times of less than 5%? They say its because of foreign VCR speeds but running times can be critical to home tapers, admittedly a more critical specification when a film runs longer than shorter but an unplanned consequence which can be annoying when looking for just the right space to copy the film to. We're talking about a three minute discrepancy here.