For a point of comparison, Planetary Annihilation does it slightly differently.
In that, there are specific amounts that given builder units use per second, for the sake of an example say 10 metal and 100 energy.
In PA, if you're metal-stalling at 50% then your builder will only use 5 metal (as in FA), but the energy usage will not reduce.
It means that you don't have the catastrophic energy stalls that can happen after fixing a mass stall. It's a simpler version of the system that doesn't ruin it in the way that Supcom2 does.