The problem could just be in the arithmetic. The two of you could both be utilitarians, even Utilitarians in the strongest sense of Mill's, but disagree on how important it is to an individual to be alive. To aim to maximize pleasure involves a theory of pleasure, and those can vary widely.
You seem focused on social good, so you would attribute little utility to simply existing. An extreme form of this end of the scale would not even consider death to be harm, if it involves less suffering than the average death an individual could expect to encounter, since some death is a foregone conclusion and an improvement over average is a gain. Just existing has little or no value (or, in the 'Buddhist' case, may actually have negative value.) This measure of pleasure is very Aristotelian, and is partaken of actively.
But many people look at the degree to which people are willing to sacrifice comfort or harm others for mere survival and assign a great deal of utility to simply being alive, perhaps accounting extra value for every person alive for every minute. Breathing is pleasant, and should continue. This measure of pleasure is very Epicurean, and is implicit in mere experience.
Since nobody is psychic and we don't have a magic hedometer, we are free to have different theories of what pleasure is 'really like' and the notion of utility is rife with such problems.