Finally I measured things, and here's the results. First of all, the pot fills up at 5-1/4 cups, or 42 fluid ounces. According to Wikipedia, the standard coffee cup unit of measure is 6 ounces. So that means only 7 "cups" in the pot. If we believe 10 to 15 cups per pot, thats only 4.2 or 2.8 oz per cup - mighty small if you ask me.
I measured the few coffee cups in my cupboard. I would say they are typical coffee cups, not huge or tiny. The measure between 8 and 10 ounces. This explains why I'm only getting FOUR cups from a 10 to 15 cup pot!
Interestingly, there isn't a universal standard for one cup. Again, according to Wiki, the cup varies all over the place. Extrapolating from common measures, it should be 236.59 grams. But US law declares a legal "cup" as 240 grams. Almost like the mythical story of Mississippi declaring pi to be 3.00. Leave the US, and definition of the "cup" is even more uncertain, if at all.
So grab a pint of beer, and let's toast the metric system. It's been around for more than one deca-score years, and can be easily mastered in one fortnight by even the slowest of students. Cheers!