this is not answering your question but i thought it could be helpful. i did a rough survey of the winners the last 22 years. my defintion of pairup may be a little different than TGJB but here it is:

New TOP -41%
Bounced but still won - 12%
paired up new top - 25%
matched prior top but less than last race -22%

then i looked at the last 10 years. The percentages were about the same. bottom line is 2/3 of the winners ran as good or better than previous race. 1/3 ran worse but still won.



BB