There are several valid recipes for mixed metal ingots.
The basic one has refined iron in the top row, bronze in the middle row and tin in the bottom one.
It looks like on your screenshot that you might have put normal iron instead of refined iron.
I see that force updating fixed it. so my eyeballing of your screenie was mistaken. Never trust a MK1 eyeball
Valid mats for the top slot is either 3 refined, 3 steel or 3 titanium
valid mats for the middle row is bronze. either of the 3 varieties of it. (they can even be mixed within the row. 100% equivalency)
in the bottom slot it has to be either type of tin, or all aluminium.
The amount of mixed metal ingots you get is dependent on witch variant of the recipe you use.
the most expensive variant with the titanium in place of the refined iron, and aluminium in place of the tin gives 6 mixed metal ingots instead of the usual 2.