A consultant will be physically on site to conduct the assessment, so if he arrives and the location has no windows, he'd select "N/A" for the grade of that field. Not sure if you saw my reply to myself, but I was able to use your code and make it work.
This is an example of what I did for one category:
var number blank = ToNumber("N/A");
Average(
If([Signage Lit / Easily Viewable Day & Night]<>$blank,[Signage Lit / Easily Viewable Day & Night]),
If([Reader Board Working]<>$blank,[Reader Board Working]),
If([Entrance / Exit Obvious and Easily Understood]<>$blank,[Entrance / Exit Obvious and Easily Understood]))
Thank you for your help!
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Michael Martin
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