The first set of results are in--and while my data is substantially more sophisticated than what I'm smoothing over here, these are the numbers:
* -8 Damage Mods (vs. Everything): 1/3rd of your character points (AP)
* -4 Damage Mods (vs. Everything): 1/4th of your character points (AP)
This ratio holds true at 16, 32, and (roughly) 64 AP. There is also a /floor/ on these abilities which I /think/ (but have not proved) is 4 AP for -4 DM and 8 AP for -8 DM respectively.
I want to take a break from the Giant List of Attacks to test Fast Company a little further. When I get home.