It’s already possible to make oil from asteroids in vanilla. You can use the “simple coal liquefaction” recipe from Vulcanus to turn coal, calcite and acid into heavy oil. And those three can be made from asteroids. So, the promethium refinery recipe is not needed, it’s only bloat.

Then don't use it?
How about this;
Using the simple coal liquefaction chain, it's 17 machines to run a single refinery running Simple Coal Liquefaction at rate without modules.
The Promethium recipe is five machines to get the same output

Oh, my bad! I just assumed that you added it because you weren’t aware of the simple liquefaction thing. But it seems you intended it as an efficiency upgrade, which makes sense.
Now that I look at them, most of the promethium recipes appear to be efficiency upgrades to previous methods to obtain the same resources. I guess I should have noticed that earlier.

Yeah, they're intended to reduce either number of machines, number of steps, or increase yield, or any combination of the three. The Oxide promethium recipe technically makes you use more machines, but your yield is increased largely.
Sometimes we overlook things, like how I overlooked acid neutralization for power production on Vulcanus, and how it's actually strong enough to beat out solar+accumulators.