Because I was explicitly told not to alter the way JIT0 and JIT1 worked. Hence I cannot fix any exploits with them.
Implementing JIT2 should not change how JIT0 and JIT1 work. If you proposed a patch to include JIT2 that altered the other JITs, it would be bad.
Proposing a seperate patch which 'fixes that exploit' is a completely different story with two possible outcomes:
A) It's accepted, because everyone feels the same way as you about that exploit and agrees that it's a good idea.
B) It's rejected for some reason or another.
If the result was A, you got what you wanted, and different JIT-settings would still be consistent. Pak-devs probably raise the required input manually.
If the result was B, then it's rejected. It would be very bad practice to sneak it in regardless, concealed in a larger patch, no?
Part of the motivation behind JIT2 was to help with exploits and nonsense like this.
Maybe, but it's "JIT2", not "Play the game as DrSuperGood deems best".
As a JIT-setting, it should only deal with how many goods are sent on their way, not how they are consumed.
This is not a valid comparison. Drive on left is largely a visual thing and was added to not change how anything worked [...]
A valid comparison would be a setting for Russian driving regulations or EU driving regulations. This might alter how cars work and act at intersections and crossing and if an unintended exploit existed in one of the modes it might be fixed in the other during implementation.
My example was too random, but you fixed it for me with hypothetical driving regulations. It was "added to not change how anything worked", as far as we understand it now. Though I never used it, so for all I know, it could include British driving regulations and behaviour. If you had asked me, or I guess most people, JIT2 was implemented to deal with stop-and-go behaviour, and that's it. I would not have guessed what else it does.
Sure, British driving regulations in drive_on_left would make sense in a way - but only if drive_on_right already had some. If drive_on_left was the only thing that included driving regulations, it would be just as wrong and shouldn't do that. Either drive_on_right got driving regulations as well, or driving regulations would have to be a seperate option, that can be turned on or off and then change depending on which side you drive on.
This is because one of two things is true:
EITHER everyone wants driving regulations - than it's wrong that those who use drive_on_right can't access them
OR not everybode wants driving regulations - then it's wrong to force them on british players
And it works exactly the same with your reasoning for splitting inputs. If everybody wants it, great, implement it for everyone as standard. If not everybody wants it, don't force it on people who just want to remove stop-and-go-order-behaviour. It does not matter whether it's a good change or not, if there is no technical reason to constrain it to another setting, just don't.
Now a sidenote about whether or not your exploit-explaination actually makes sense:
For best play experience, you can't fix everything with the base game functionality, you also have to consider the pakset. 300% to 60% is significant, but if the pakset author was smart, he could have balanced it in a way where you have to deliver that 300% amount of oil to make the same or less profit as if you would delivering the 60% chemicals. You would need to invest much more to get the oil flowing (even more so from an oil platform, operating a harbour), and would rather build routes for the more profitable chemicals and ink instead of investing as much again. Would not be exploitable if done right, in fact, if the pakset was balanced like that, your "removing the exploit" just destroys a wonderful balance, and players just get cheaty cheap chemicals that were supposed to cost them much more in oil delivery.
On the other hand, say there are more consumers for chemicals than for ink. In order to deliver to all of them (which you want to do to maximize profit), you would have to connect every single refinery. At least, that's what's supposed to happen with the current factory generation. Therefore, you have to use them all just for chemicals, and any ink that is also used is just a bonus.
I don't think it's a matter of exploits, it's a matter of pak balance. The way I plan the p192c factory overhaul, my refinery will produce Naphtha, Fuel and Heavy Oil, because Crude Oil is split into those parts with different heats, it produces parallel. I intend to make it that generally two of the goods need to be used to make a profit, because it can't be profitable to throw 2/3 away. This, to me, would make nice gameplay. JIT2 does not help, it just messes up the balance.