Vignette ALT with question - Testing tomorrow

[dmlarch]

Coach,
My question involves the joist depth on the second floor. The worst combination is a 36" depth duct with a 24" duct. The section cut however is through a 24" joist. Am I correct in allowing the worst case 36" space between the top of the duct, but drawing the 24" (which is where the cut-line is through) in section. This means there would be 12" from the top of the duct to the 24" joist in section. This is the logical way to do it and the way it would be built, but just wanted to double check.
Thanks-