Explosives recipe progression don't seem to make sense balance-wise

[leandor]

Before creating this, I searched for another issue that mentions this issue... but didn't found any (unless I'm blind.) I'm not sure I'd catalogue this as a 'bug', though.

In my game, late to end-game, I have access to 3 different recipes for the basic item Explosives:

• I: the basic vanilla recipe that accept prod modules and just uses Coal + Sulfur + (purified)Water
• II: A second tier recipe that consumes Nitric Acid + Sulfuric Acid + Glycerol Liquid + Coal
• III: The last tier, that uses Toluene + Nitric Acid + Sulfuric Acid and no coal, but returns sulfuric waste water.

Both II and III don't accept prod modules. III is better than II in the fact that returns part of the sulfur used as sulfuric waste water, But nothing beats I in the fact that by using prod modules, you can reduce the mat requirements a lot!

If you take into account just the sulfur consumption (and remove prod modules from the equation), I, II & III seem to be properly ordered as sulfur consumption goes from 22.5 -> 14 ->9.4 (per 45/s explosives.) Also Nitric Acid drops too from II (~560/s) to III (375/s), which makes sense too.

The only thing that seems to be altering the balance is the fact that the first recipe allows for prod modules and the other two don't... not sure which is the intended one. Explosives allowing prod modules is vanilla behaviour (intermediate) and maybe all 3 recipes should allow them... not sure.

My mod list (in case it's of significance):
-> https://pastebin.com/PqsK5cGE (taken from factorio-current.log data loading phase.)

[leandor]

I've been thinking a bit about this issue, and from what I could understand the reason why upper tiers of Explosive recipes don't accept prod modules is due to stoichiometry, perhaps? I.e. the two later recipes are more closer to the actual chemical reactions, while the first one is more 'abstract'.

In that case, I understand that issue and the reason... but I'd argue that the 'explosives' item in-game is already abstract enough for prod bonuses to apply to it without regard of actual chemical formulas: i.e. in my mind, it could be the assembly of the actual explosives package that's getting prod bonuses, not its fundamental constituents.

In a sense, it's already weird that mixing sulfur+coal gets you the same item that you also get via the TNT path, so in that regard, for the second and third recipes, one has to assume there are a hidden step in the chain that goes from the product of the chemical reaction to the actual 'packaged' explosives that's produced... I'd argue that's the step that is getting the prod bonuses.