https://github.com/NillerMedDild/Enigmatica2Expert/blob/92af8c610b66967fff8818af93b0a716cd4bf1d9/scripts/TinkersConstruct.zs#L36-L39
Author of PlusTiC here. This should be 432 and 864mB of Alumite, respectively, not 216 and 432mB. 3 Alumite Ingots should be created per 5 Aluminum, but the script incorrectly specifies 1.5 ingots.

The liquid values for Iron and Obsidian should both also be doubled, as there is 2 iron and 1 block of obsidian (=288 mB) per 5 Aluminum/3 Alumite, not 1 iron and 0.5 block.

Hence, the correct alloying ratio should be

720 Aluminum + 288 Iron + 288 Obsidian = 432 Alumite
1440 " + 576 " + 576 " = 864 Alumite

Thank you for noting and reporting this. I suspect that @NillerMedDild did this on purpose when designing the pack. There's more alloys in there that yield less resulting metals when alloyed. Might be for the purposes of the expert pack.

But it could be an oversight as well. I'll leave the issue unlabeled for now and leave it to Niller to respond.

Fair enough. If this alloy ratio was intentional, then it might be a good idea to add a recipe for the Adv. Metallurgic Fabricator to yield more Alumite.

There's more alloys in there that yield less resulting metals when alloyed.

I don't think this is the case, however; IIRC no other alloy in the pack is balanced this way (e.g. 1 Osgloglas = 1 of each main Mekanism metal is the same as default). Hence, I think this is an oversight on Niller's part.

For my part, I have changed the CraftTweaker script to the default ratios in my own world. I'm near late game (farming Amethyst essence for Ludicrite, in turn for Wyvern cores) and I have found this pack to be very well-designed.

This is indeed a mistake, I think at the time I was thinking the recipe would negate the ore doubling bonus, but that doesn't really apply :P

@NillerMedDild You forgot to double the Iron and Obsidian liquid values in the ratio.