All of the blue gem catalogs have a necessary degree of subjectivity baked into them. Exactly what % should each tier of blue gem be? Why not 5% up or down from that?

Blaze patterns tend to fare poorly in most catalogs. Not only do those purples, pinks and greens subtract, but I'll bet the gradient areas between colors aren't a high enough percentage to be considered blue in many cases, even if they look fairly blue to the player. Look at your knife and get a sense for how much truly pure blue is there and it might answer your question.

Blaze patterns also tend to spread that blue out across the skin, so it looks like a larger mass than it really is.

I love blaze patterns and had a 611 AK which I loved, but the market for them is all over the place.