Your point about having a lot at stake seems not to be needed. You would sacrifice much more than the helping-a-friend bonus, but less than their stake.
This just means that helping is reimbursed at the rate less than one-for-one, but with a positive bonus in the beginning; also, receiving help gives additional bonus at the rate less than one-for-one.
From my experience I can say that you get reimbursement for some combination of the friend’s observed happiness and extrapolated happiness. First can be quite coarse sometimes (and not always available before the event), second is based on modeling your happiness in the same situatuation (and can be modified by previously learned corrections) and has a systematic error because of this.
Your point about having a lot at stake seems not to be needed. You would sacrifice much more than the helping-a-friend bonus, but less than their stake.
This just means that helping is reimbursed at the rate less than one-for-one, but with a positive bonus in the beginning; also, receiving help gives additional bonus at the rate less than one-for-one.
From my experience I can say that you get reimbursement for some combination of the friend’s observed happiness and extrapolated happiness. First can be quite coarse sometimes (and not always available before the event), second is based on modeling your happiness in the same situatuation (and can be modified by previously learned corrections) and has a systematic error because of this.