Some years ago in response to a thread much like this, we pulled this together.
https://dwarffortresswiki.org/index.php/Masterwork:Metalit gives usage notes as well as the raw numbers.
(edit: Oops, sorry i didn't see that you were already using this Wiki as your source, i read your original post on my phone. sorry for any confusion that caused
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According to that wiki page mithril is actually a little better than steel, just a little but enough to be worth the upgrade if you can (for armor and edged weapons only -- it's much too light for hammers). Since Meph remembers otherwise, I am not sure if that info is still up to date. Maybe someone with the game at their fingertips will check. If not i can look it up this weekend.
The results of the simulator looks a little off to me. In game, edged weapons will do fine, and "piercing" (very small contact edged weapons) will do very fine, at penetrating armor. Especially if armor is of metal inferior to the blade. From your description it doesn't seem like the tool takes into account the weapon user's size or strength, which matters very much. Small wielders might want to stick to spears, large or strong wielders can use blunt or wide-bladed weapons.
In Dwarf Fortress, as IRL, armor can deform without failing, hurting or mangling the wearer inside, which I'm also not sure the tool is telling you anything about. There is enough fidelity in DF's metallurgy model to capture that metals can be strong (not deform much) or tough (not break easily), or both. Steel is pretty good on both counts so it is a good baseline. Crystalline weapons (ashglass or ebonglass) are strong but brittle -- their fracture toughness isn't better than steel, but they shouldn't deform and crush you inside at all before they break. Orichalcum and especially deep bronze are very tough, but still somewhat deformable.
Finally, different metals can have relatively better resistance to impact (orichalcum) or shear (mithril). So, if you are really detail oriented you might want to layer mail and breastplate of different materials.
Volcanic is superior to all other modded metals for everything, so if you have that, basically you should use it. and adamantine is still best for armor and blades.
I didn't think dwarves can make deep bronze. But I haven't played a full game in dwarf mode for a very long time.