Hello.
The mods are similar but there are some differences.
Inverted Oil Refinery adds hardcoded recipes that the author of the mod has (probably) manually created to be inverted of the oil recipes.
Fluid Permutations dynamically generates all possible permutations (see picture in information tab) of all applicable recipes. This means that for certain recipes you have more customization options and that Fluid Permutations works with recipes added by other mods and inherently it will not need to be updated if another mod, including the base game, changes its recipes.
Fluid Permutations' way of changing the recipes is with hotkeys.
Fluid Permutations hides its recipes from the technology screen and the recipe selection dialogs so that they do not clutter everything.
