OK. Here is one possible approach. What do you all think?
210.52(A)(2) clarifies what is meant by "wall space." But it starts by saying, "As used in this section. . . ." Since (A)(2) is part of (A), I infer that that clarification only applies within (A). Specifically, it does not apply to 210.52(C). In other words, we don't have a clarification of what is meant by "wall space," in the context of "countertop wall space." Therefore, we cannot begin by saying a floor-to-ceiling window in the family room counts as wall space, and conclude therefrom that a countertop-to-ceiling window in the kitchen also counts as wall space.
I am inclined to go with Tim's post #2. It's not "countertop wall space" because there is no wall, and because we don't have a rule that says a window behind a kitchen countertop counts as wall space.