Because you, murrdog, were arguing, like always, about the track being prepped SOOOOOOOOO much better on a Saturday that you on your dumpy street tires were able to run 13.2 on said Saturday and it drastically dropped to a 13.7-13.8 on a Wednesday night.
The track prep, from personal experience, made my car hook shittier due to wheel hop on street tires. I feel someone on slicks will gain more from track prep