files speed up to 100.15% when importing to FCP

Hopefully I don't make any heads explode with this one. I've been editing for 10 years and this is the strangest problem I've ever run across.

STRANGE PART 1
I'm editing interviews shot on DSLR's from two angles, and syncing them up with audio files. When I'm importing DSLR footage into FCP7 (and my assistant had the same problem with FCP6) the video clips speed up by about 0.15%. So a file that's 12min 21sec long will import as 12min 19sec 20 frames (out of 23.98)

I have about 80 interview clips where I have to sync the audio and it's making it impossible to sync things up without going through a laborious workaround.

STRANGE PART 2
The files also get shortened on import to FCP X, however the multicam system on X syncs up the audio flawlessly. The irony is that FCP X sucks at exporting Multicam clips in XML files to FCP 7 (yes, I have Xto7)

STRANGE PART 3
I've gone back to past projects and tested out other files, shot on other cameras, and FCP has the same issue with all of them. No matter what version of FCP, the file shortens by a bit.

STRANGE PART 4
The files shorten on my computer AND my assistant's computer

POSSIBLE IMPORTANT INFO
To give you a brief history:

I recently went freelance and switched from 7 to X. Had a client who was giving me a lot of multicam stuff that I was editing with no problems in X. Decided to switch back to 7.

Before going freelance, I usually shot and edit my own footage, but have recently been getting the .mov files without a camera directory structure from the client, which FCP X processes fine. Could the fact that I'm not importing directly from a camera (or folder w/directory structure) be causing this?

Hey Jessica thanks for your reply, I'm getting it from reading the file info in the MAC OSX finder window.

The problem is that it's happening with every video file on my comp, so finding a temporary workaround like speed change doesn't make sense. I can't be slowing every clip down to 99.85% for every project I ever do after this.

found this thread on creativecow http://forums.creativecow.net/readpost/8/1151488

I seem to be having the same issue....I'm on FCP 7, but X does it as well. And my friend says it happens on his machine? Is this just a big glitch that most people have but which has never caused major problems for people?

I'm having audio sync issues as well, but it turned out this issue of changing durations was NOT the issue, as the clips synced up again once importing in the timeline.

To test it, I took a 3 hour clip from a previous project and created a wav audio file from it. I then imported the wav file into FCP7 and it read as being about 11 seconds shorter than the video clip it was created from. But THEN in the timeline they synced back up.

Took me a long time to realize this was NOT the culprit to the syncing issues on my current project