MF Calculated?

What do you guys think and what have you noticed throughout all the MFing you've done thus far with the patch. Is MF on Act Bosses calculated, or not? I honestly can't tell. Some of my friends swear by that it is, and others swear that it isn't.

I might take the time when I am done finals this week, and sit down to do like 250 runs on Meph with no MF and 250 with 400+ MF and post my results. If anyone has done any sort of testing like this already, and has somewhat conclusive numbers, let me know.