That's really interesting - I am not seeing the same behavior. I'm seeing huge variation in the number of credits awarded, from ~40 to ~142, with an average of 60.79 (damn close to your fixed value).
Since you did it, I went in and calculated numbers, and I'm seeing a similar gain. My number of normal WUs is fairly small, but I was getting 48k/day on a 570 normal, and 59k/day with the app_info file.