I get the OPs point. Trial Synthesis is like a simulator. It really shouldn't matter if we could click those buttons for using HQ materials and have those factored in.

With that said, this sort of improvement should be both low-hanging fruit (easy to fix) and low priority. Do your trial synthesis, see where your quality caps out... let's say... 8200/10000. Then add your HQ materials in the window. You need them to be worth at least 1800 quality in order to guarantee an HQ (barring Good/Excellent states).