This isn't a problem, just something that I noticed today after using the camera for a year and a half.
In Premiere Pro CS6, I noticed that every clip that is under a minute long either ends with .00 frames or .15 frames - for example, there are no clips that are 7 seconds and 23 frames long. They are either 7.00 or 7.15 - so either they end at a half second mark or a full second. Check out the attached picture to see what I mean.
Like I said, there's no issue or problem with this, I was just curious as to why this happens? Is it something with the way the files are stored on the memory cards?