In response to the part I have bolded. Again, I never said anything before because I didn't know if it was just me and I didn't want to look like some fool, but now that you mention that specific mileage, I too have experienced just this. In several of the regular online Seasonal TT's, I have noticed big sudden improvements in the car and also in my times, right around the 200-250 mile rage. It was weird as I'd be going along and not even coming close to my ghost, then all of a sudden...bam, big improvement, always around the same mileage, 200-250 or a touch more. I can say I have noticed this behavior in about 6-8 Seasonal TT's so far. I would only notice this obviously in Seasonals that I put a lot of miles in. Now that other people are coming out and telling their stories that match mine, I don't feel so crazy.
I really don't know what to think of this though, it is kinda weird. Let the conspiracy theories begin.