that stinks but:

Sample size + probabilities = putting too much stock in 20 runs is gonna be often unfun, and a bad time

I just did 5 runs and got 3 speed pieces. 40%.  If I'm getting 40% everyone must be getting 40% all the time. 

Op, it must not be a constant.  I just did 7 more runs and still only got 2 speed pieces.  35%.  We'll figure this out eventually.

I got 100% rate. But I was farming the campaign. :))