Q: Project files creating dup assets (but not imported via scan)

I've looked at these two threads: http://discussions.apple.com/thread.jspa?messageID=9147105#9147105
and
http://discussions.apple.com/thread.jspa?messageID=9096958&#9096958
which sort of address my question.

I do not import media via scan. I am attempting to import project files with associated media. I import a project file and it imports the media assets as well. Here's the problem. When I then go and import another project file with many of the same assets, FCSvr creates duplicate assets, but only if I import the second project file soon after the first. I waited a week and tried it, and no duplicate assets were created. I have setup periodic scans on my Library Device which is an EIP device and which is where I'm sending the files that get imported. The scans are setup to run every 10 mins or so but don't seem to have an effect. So why does this work if I wait more than a day or so and can I manually kick off the scan or whatever process I need to setup so that I avoid getting duplicate assets.
Again, I don't want to originally import the media via scan of an EIP device b/c I want to do set some metadata fields on multiple assets but not all assets in the project.
I'm really just curious what process it is that tells FCSvr that these assets already exist in the db and filesystem and how I can manually kick it off.

Any enlightenment would be great.
Thanks.
H.