What is it - Analytic surface?

[Anonymous]

What is it:"Analytic surface of openings on the reference line side"?

[Anonymous]

I believe it refers to the calculated area of the openings (as opposed to the nominal size) on the reference line side of the wall (the edge with the heavy cursor).

[Anonymous]

Matthew wrote:
I believe it refers to the calculated area of the openings (as opposed to the nominal size) on the reference line side of the wall (the edge with the heavy cursor).

Why?