seems still a big trouble
I tend to my initial idea now,
if event no happen, change price from 1 to 0.5
next round, if it not happen, change price from 0.5 to 0.25
....
based this rule, if a loser ask for settlement , he still can get value 0.5
if he didn't ask for settlement, in next round, even he win, he only got value 0.5, if lost agian, he only got 0.25, so it's very stupid if he didn't ask for settlement.
if all users have settlement completely, the price can reset to 1 again.