[CSS21] stack level definitions in 9.9.1

There are two definitions of the term "stack level" in 9.9.1

A: "This integer is the stack level of the generated box in the
current stacking context"

B: "Each box has an integer stack level, which is its position on the
z-axis relative to other boxes in the same stacking context."

This coexistance continues in the overview of layers "Each stacking
context consists of the following stacking levels" [1.-7.] and
vanishes in Appendix E.

Do the terms "stack level" in A and "stack level" in B have the same meaning?

-- 
Ingo Chao
http://www.satzansatz.de/