Ok so I've tapped my beer now and I have to say that for me, "flameout" addition hops in a No chill taste like 15 min hops in a boil. As I indicated above, I had Magnum for bittering, plus 3oz US Goldings in at flameout. The beer is quite tasty, definitely not over-bittered. Its 100% Pale Malt, meaning no crystal malt, so if the flameout addition contributed much bitterness, it wouldnt have any crystal malt to hide behind.
My beer is fairly low in hop aroma, but big on hop flavor. It feels like there ought to be about 25% MORE flavor than what I'm getting, given than I used 3oz at flameout, but it might be that US Goldings are pretty mild, and I haven't used them too much in the past.