I have my own pet theories about how to find "natural zeros" in value systems, but this comment is already rather long :-P

Please, do tell, that sounds very interesting.

It seems to me that systems that put "zero point" very high rely a lot on something like extrinsic motivation, whereas systems that put "zero point" very low rely mostly on intrinsic motivation.

In addition to that, if you have 1000 euros, and you desperately need to have 2000 and you play a game where you have to bet on a result of a coin toss, then you maximize your probability of ever reaching that sum by going all in. Whereas if you have 1000 and need to stay above 500, then you place your bets as conservatively as possible. Perhaps putting zero very high encourages "all in" moral gambles, encouraging unusual acts that might have high variance of moral value (if they succeed to achieve high moral value, they are called heroic acts)? Perhaps putting zero very low encourages playing conservatively, doing a lot of small acts instead of one big heroic act.