PAP

Did you like doing your back squat workout like this today?  Going back down a couple times after hitting a heavy double.  It probably felt good to go back to a lighter weight after hitting a heavy set.  This phenomenon can be explained by the idea of post activation potentiation (PAP).  PAP essentially means in this case that by doing a heavy double, you are firing more motor units and type 2 muscle fibers (fast twitch) as compared to the lighter weights, so when you go back down to the lighter weights, you actually physiologically have more muscles to recruit and fire, in turn making the lighter weight feel especially light. 
Here is Andrew, Doug and Scott getting some of those squats in.

Workout:

3 Rounds:
6-4-2 Back Squat
*weight can go up within round, from six to four to two, but use that same weight for all three rounds