For whatever reason the target recipients did better with their actual blood type. B- being 2% of the population (and half of that being CMV+) put it in high demand in that small audience (which is why I give myself a bronze since my bloods high value has such a narrow focus). Or so they said. All I know is that I donated gallons of the stuff, along with a shit load of platelets, because they said very young children needed it for the above reasons. Sounded good enough for me.
Like you I then I went to Iraq, donated a bunch there, and was told on my return no more blood drives for 5 years.