Replaces EFF with EPM in the build hover. - https://github.com/JustinLove/energy_per_metal - http://wondible.com/pa/energy_per_metal_v1.0.0.zip - PAMM
It's the inverse. This is energy/metal. Eff was metal/energy, which was such a small number that it got rounded into oblivion. An alternate improvement would be a percent, which would effect a x100.
The base game uses such small numbers (0.01) that they get rounded into oblivion and it's hard to tell one from another. But really, this is a minor personal preference mod - if you don't know why you'd use it, just don't use it.
Oy, another mod that didn't get on my list. This one isn't completely redundant, but the problem it was solving is gone, so I'm just going to obsolete it.