Maybe when you have a rebuy tournament, your initial buy-in is lower, meaning there's fewer points up for grabs to start out, and with the rebuys and add-ons the points get fractionalized further. In our case, our freezeout tournaments have $25 or $40 buy-ins, and our one rebuy tourney has a $15 buy in with $10 rebuys and a $10 or $15 add-on. To increase the points a bit in the rebuy event, we change the formula in that one to
square root of the prize pool times the average prize pool per player against that average against what they spent, or ...
sqrt(pp * ((pp / n) / ((pp/n)+rc+ac)) / (r + 1.0).
Using our rebuy example, say you have a 10-player, $15 buy in with $10 rebuys. Say there are 10 total rebuys, 1 player doesn't rebuy, 1 player rebuys twice and everyone else rebuys once. Here are the 1st, 2nd and 3rd place point totals for:
The player who doesn't rebuy: 7.91, 5.27, 3.95 (the exact same as a 10-player, $25 freezeout)
The players who rebuy once: 6.68, 4.45, 3.34
The player who rebuys twice: 5.89, 3.92, 2.95
Otherwise, the freezeouts are just the square root of the prize pool divided by rank + 1. I love Neau's formula, it rewards those who win bigger buy-in and bigger field events, and also rewards those who do well in rebuy events who spend the minimum, or closer to it.