Interesting that the pitchers 100% ESR is almost always less than the batters 100% ESR.
Thoughts on why?
My theory... there are 13 pitchers to 12 position players on a club. 8 of the pitchers are in the bullpen and tend to be much lower levels compared to their starting bretheren. Additionally, of the 12 position players, only 3 are generally "lower level" and on the bench.
As such, it would seem that clubs are showing a tendency to save money in the bullpen and spend it on starters/position players. (That's how I do it as a GM, btw)
If you assume that a full salary cap can afford a team of average level x5 (lvl 5 for tier D, 15 for C, etc) then..
13 pitchers averaging x4 and 12 batters averaging x6 would come out to a split of 130 skill points. Divided by the number of pitchers, you get an average ESR delta of ~10 (130 / 13).
Deltas by tier, as of "Middle".
I would expect these deltas to be largest at the beginning of the season, when you have your slew of x1-x3 pitchers in your bullpen. By mid-season, they've gained 2-3 levels compared to 1-2 levels of the higher level position players. A clear example is Tier A, where the delta decreases to 5 by the end of the season. I suspect this is due to the number of 45+ position players that were signed versus low 30s pitchers. Given the uniqueness of the tier (you can sign any level, but the salary cap is designed around the 30-40 tier), it's VERY clear from this that most of the league is following the same strategy of stocking up on big bats and little arms.
Honestly, if I were you... I wouldn't share this data as it could be used by GMs to gain a competitive advantage.
For example, knowing that the pitchers in Tier A need 13 fewer skill points than the batters to reach 100 ESR means that you can try two different approaches:
1) Spend more heavily on pitching than you would otherwise, hoping to have an extremely dominant pitching staff.
2) Limit your spending to match the ESR for an "average" pitching team, pushing the extra cash into signing higher quality position players.
Of course, since the ESR changes so dramatically during the signing period, you'd have to be ontop of keeping it up-to-date while managing your signings.