The first of your hypotheses is correct. For saturations below "fancy light", GIA takes the position that there is not enough colour in the stone to be able  to assess its distribution reliably, and thus does not grade it. Hence the "Not applicable" note. If the distribution of colour is not even, GIA will note it as "uneven" - see this one as an example



As far as I know, the owner has no option to ask GIA to omit or include certain information; the only "getaway" is to order a type of report that does not include certain information (e.g. the "Color Origin" report has no clarity or finish grade)

You are most welcome. And since we are on the subject - welcome to CDI!

I was perusing old posts when I came across my first post.  I just wanted to let you all know that I did purchase the diamond back then BD, before David, and hope to have David and his crew set her next year (end of the year - it's been a whopper year for jewelry purchases).