- take the ranks that will be chopped

- determine which prizes are awarded to those ranks

- add up the total cash and total points that are awarded by those prizes; this is the pot to be split among the chopping players

- add up the chips from the chopping players; determine the percentage each player has

- multiple the pot by each player's percentage to arrive at what they get

Example: There are prizes awarded to 1st through 10th places. Last 4 players are chopping, so they split prizes for 1st, 2nd, 3rd, and 4th place. 1st is $1000, 2nd is $700, 3rd is $300, and 4th is $100. So total pot is $2100. Chipstacks are 1000, 800, 400, 350. Total chips remaining in play are 2550.

1st place has 1000 / 2550 = 39% = $819

2nd place has 800 / 2250 = 31% = $651

3rd place has 400 / 2550 =16% = $336

4th place has 350 / 2550 = 14% = $294

I understand your situation, and unfortunately the chop dialog doesn't allow an easy way to do this. I've been reluctant to change the behavior of the dialog because, frankly, it's complicated enough as it is. But it's on my long, and getting longer, list of things to do.