I post this in honor of Tims work on PL and BPP. Bill Lyster and I have been working on using AI to analyze our database of over 4700 races. As novices using AI, we may make a mistake or two, but I asked AI this question in 3 different ways and got similar results each time and each time the results agreed closely with what Tim was finding. AI broke down the results by surface and distance. (Remember for consistency line selection is automatic in the data base set to best of last 3 surface and distance.)
Since I did the study 3 times and got virtually the same results, I feel comfortable sharing the AI report with you.
Here is the report. Any mistakes that you find are entirely my own.