Probably not, Jen.
This test seems MOST useful for determining who is at greatest risk of severe anaphylaxis. Those of us who have already seen those kinds of reactions... well, we already KNOW the answer and so it doesn't matter very much knowing which particular protein is the allergen.
For those who are diagnosed via a skin/blood test after a very mild or localized reaction, though... this information could really be helpful. There are some proteins which are much less likely to provoke life-threatening reactions than others in allergic patients. In other words, it probably makes little sense to have a preschool go peanut-free if the risk is relatively low to begin with, and that is a family that (though they'll carry epinephrine) will be able to enjoy a much less restrictive lifestyle than a patient allergic to one of the markers for severe anaphylaxis (I'm recalling there is a breakdown between Ara h2 and Ara h4 sensitization, but please don't rely on my memory!).
The down side is that this is inherently a game of statistics, so the conclusions will become clearer (and better-validated) as more patients participate in this kind of testing. At the moment, I'm not sure that it *is* clear how valid the conclusions are, since few patients like your DS or my DD have bothered with testing like this (for obvious reasons-- there's not really a medical need to do it since we already know that they're in that highest risk group). There are exceptions to those broad categories, too, and there are certainly proteins (and therefore potential allergens) in peanut other than those included.
Does that help??