So further investigation revealed Dremel bits are the same size as this machine takes and I have a ton of dremel bits. I've spent some time trying to figure out which of my bits were appropriate because, you know, they were all just thrown together and not labeled. 

One of them looked like what I believe is called a "ball end" mill, so I thought I would give that a try. Psyche! Used the same file in carbide create, changed the toolpath to add the proper size for the ball mill specs, saved it, ran it, and now the mill doesn't even cut into the wood. Saying I'm confused is a bit of an understatement.