Question For Our Readers

If you go to the new NIH Project Reporter Web site, you can search for all supplements and revisions to existing NIH grants that have been paid with ARRA “stimulus” funds. It looks like a bunch of these were paid exactly 50%/50% by one or another Institute and the Office of the Director. These supplements range in total amount from about $10,000 to about $50,000. Anybody have any clue what these are and why they’re paid 50/50 like that?