Given the way your sprites ingame look, I'm gonna guess that your art skills are about as crappy as mine (no offence meant of course). It's still a bit hard to differentiate modules 4, 5 and 6 though. I think it'd be a pretty clear distinction to have them be like modules 1, 2 and 3 (so with 1, 2 or 3 illuminated balls, and 2, 1 or 0 dark balls respectively), but with the darker tint like you did for productivity and effectivity modules. I think this would make a great difference in being able to differentiate between the levels.
Also, if you would decide to keep this mod as a small package (like I mentioned in my other post), could you look into sorting the modules properly in the crafting menu? Productivity modules are sorted properly, but speed modules go 1-4-5-6-7-2-3, and effectivity modules go 1-2-4-5-6-7-3. Very confusing, especially combined with the the sprites being the same.