It's more a convenience issue than a big money maker.
Like I said, it's definitely not worth installing on every factory, only where it can be difficult to fight for limited supplies of energy. The point is not to make every factory much more profitable, but to give the player more freedom and flexibility to customize a factory as they see fit. As it's the option with the lowest price tag of all 4, you'd expect it to make the least . . .
Also, new closed loop structures can be determined using this cycle time and production ratio. For people that like to set up closed loops, this energy efficiency may well be worth the investment. (but I don't want to post answers here, it took me a long time to figure out a good sol'n on paper. I don't want to spoil it for anyone who wants to think it through
) But if you want me to pm you why I made it the way it is, I can do that.
There are a lot of things to think about and consider before you decide to install one. This was precisely my intention. They're only good / useful if you make them useful. You can't just set them up on every factory and say, 'let 'em rip'
Sorry if that seems like a callous answer. I can't stand anything remotely similar to a 'cheat script' I'm not out to make your life easier, I'm actually looking to make it harder by forcing you to make more decisions and think through more issues. (which you seem to be doing admirably)
Keep plugging away
"Nature's first green is gold" . . . stay golden.