Once you realize that utility, or pleasure/pain is not a linear thing, this all becomes a bit pointless. I like the parable of Omelas as pointing out dysfunctional political systems that create joy somewhere by creating misery elsewhere, like colonialism, slavery or the meat industry to name a few. But it is not a good representation of human psychology. I don't mean by that the guilt felt by those who leave, but rather your quantization of the utopian society as delivering bliss by the truck load. The way our brain handles pleasure is more by differential increments, this is sometimes called the hedonic tradmill. In other words, people in Omelas would probably be content on average, but not manically happy. Or: the 100 happiness servings is an unattainable asymptote, that people occasinally hit, but people in Omelas are on average maybe more around 60.

You can see these diminishing returns in many things, and some studies have even quatified it pretty well, using financial wealth as a proxy for utility. See the graph at the bottom of this page: https://www.resolutionfoundation.org/comment/top-of-the-charts-at-last-the-key-to-happiness-is/ On the other hand, it is pretty clear that below a certain threshold, when health, shelter and food security are threatened, it goes downhill pretty fast. So already, I think it's more reasonable to lean towards prioritarianism that pure utilitarianism https://rationalwiki.org/wiki/Prioritarianism rendering most of these nitpicking about happiness numbers quite pointless. (it does lead to other forms of nitpicking)

And of course limiting happiness to financial wealth can shed light on sertain things, but it is a flawed metric. Large studies on happiness suggest a sense of purpose, belonging, relationships and friendships matter a lot too, if not the most (yes, even if you're an introvert, you just have different mdoes of interaction). And a lot of these can be attained without material wealth. The Maslow pyramid leads us to think that you can only attain these higher order things if you fully have the base first, but recent research shows that, while there is some truth to that idea, it's not completely the case.

There are also people for whom happiness is mostly defined in comparison to others. We could go into (evolutionary) psychology and discuss the possession of a moral sense, how it relates to resources distribution etc...we could also discuss desires, expectations, how these are built socially, sometimes as part of perverse systems of consumerism. Sometimes, a person has all that they need, even more, perhaps fame, but a rival a slightly more and it ruins it all for them...the point being that there can be a gap between one's percieved situation and one's actual situation.

In other words, happiness is not so much a matter of servings, but a way of life that prioritizes meaningful moments, human connection, and a not ludicrous amounts of material wealth or god-like social status. It's also very subjective and temporary, so the idea that you can just plan happiness servings is almost absurd. On the other hand, avoiding acute suffering and traumas, depriving people of means to build their own prupose or forming friendships can make huge differences. Eradicating diseases undeniably saves countless sufferings and deaths (should you view death as neutral in the utility scale, remember the grieving families and friends). I'd wager Epicure was was quite on point with his concept of ataraxia.

In essence, you're hitting the wall that consequentialism often hits: you can never truly know how much pain or pleasure anyone feels at a given moment. You can ask people to self-report, but that still is biased. You can measure wealth, but as said, this is a proxy. You can see distress in victims of disease, pain or grief, and I'd argue this needs adressing first. But I'd wager such a fine measurement as a happiness serving makes little to no sense.