I can't recall the tech names correctly but those two have wrong descriptions when looking at the data banks: ~Build Arm Improvement Tech ~Commander Build Arm Improvement Tech Both state that they increase build speed by 50% and reducing resource consumption by 50%. While noticing build speed going faster, fabricators and factories use 50% more metal, only energy consumption is reduced by 50%. Same applies to the commander. The screenshot showing a fabrication vehicle using 15 metal and 500 energy. EDIT: Oh forget what i wrote, just looked at the description again. Only energy consumption is reduced. Must have missed that a vehicle fabricator now uses 15 metal and a vehicle factory 22.5. Sorry for that.
I am pretty sure they say "+50"% build speed, -50% energy cost". The amount of metal put into the building is build speed: Metal Cost/BP per second = seconds till it is finished. The energy consumption is just "wasted". You need power planets to power the fabricators/factories. There is no inherent energy cost with buildings or units like there used to be in SupCom, it is purely based on the effectiveness of the building unit.
Here are screenshots of the two techs. While it is not entirely intutive that they mean "50% more Build Speed = 50% more metal consumption", it clearly only states that the energy cosumption would be less.
