It seems that would make a serving 2 cups.
Not quite, Tasty.
As ChefRoss points out, a "cup" of soup is typically six ounces (not the 8 of a cup cup). So twice that would be 12 ounces, or a cup and a half.
But a bowl of soup is most often only 8-10 ounces.
I find it interesting, too, that you frequent places where pricing is on a two to one basis. Generally speaking, that's not the case. Typically, a bowl of soup only costs 1/3 or less more than a cup. F'rinstance, if a cup (6 oz) is $3.25, a bowl might be something like $4.50. But watch this magic:
1 cup (6 oz) at $3.25=0.54/ounce.
1 bowl (10 oz) at $4.50=0.45/ounce
Do you think it's an accident that they'd rather sell you a cup than a bowl?