That makes a lot of sense. Thanks. I was wondering how it was so mouse-specific.

So basically, we're talking about a new switch here

The problem with that is that:
a) we the newest Dells we've been getting have no PS/2 ports. I applaud this move, but it makes it difficult for our IS department, because:
b) we deactivate the USB ports in the BIOS on all our machines (we don't want people bringing in thumb drives and other hardware. It makes our jobs simpler and this is the easiest way to do it)

So, given these two things, it looks like there are only two choices: have the old and new K/M, or just have the old ones Oh well.