TCEC FRC4 Unbalanced Books

In last week's post, TCEC C960 FRC4 (January 2022), I mentioned the use of 'unbalanced books'. Wanting to know more about them, I downloaded the PGN files for the last two stages of FRC4, where they were used, and analysed them. For the 48 games in the 'Final League' (i.e. semifinal) and the 50 games in the final match, there were 32 different start positions (SPs), distributed as follows:-

2 : 18 positions
4 : 11
6 : 3

The first column shows the number of times a position was used in a game. In other words, 18 SPs were used twice, and so on. Since each SP was played twice, each engine in turn taking White, this is the minimum. I once attempted to calculate how much each of the 960 SPs were scrambled relative to the traditional start position. The results were summarized in A Chess960 Almanac (October 2011).

Is there a correlation between 'unbalanced books' and the degree of scrambling? A preliminary analysis was inconclusive, but 32 different SPs is too small a sample to decide one way or the other. I hope we'll eventually get enough data to say for sure.