They probably want the latter two events to synch up with something in Vegas (notice that there's always a big fight on Derby Day in Vegas---this year it was Manny and Mayweather).
Not only are you right about this year, but Mayweather historically has scheduled fights around that month and date. I just assumed the line that he was fighting around May 5 or Cinquo De Mayo to cash in on the Mexican American fight gate and ppv money.
Now that you mentioned Derby Day and Vegas.....it makes more sense.
Now....who cut off Khartoum's head?
