Set one number on Settings — the price of a share. On Members, type each person's name and how many shares they bought; their savings compute at once. On Income, enter the interest (service charges), fines and any expenses. The Share-Out tab then does the fair maths: value per share = the whole fund (savings + distributable profit) ÷ total shares.
Because every member's payout is simply their shares × that value per share, nobody can dispute it — the arithmetic is identical for everyone and visible on one tab. It's the exact calculation that causes arguments and dissolves groups when done by hand, made automatic and auditable.