I understand, but for mass reactor it makes extractor, fabricators and commander upgrades totaly useless :
Tech 1 Mass reactor : +5 mass/s (56 mass cost), near no energy cost -> 0.090 efficiency
(Last FAF values)
Tech 1 Mass extractor : +2 mass/s (36 mass cost) -> 0.055 efficiency
Tech 2 Mass extractor : +6 mass/s (900 mass cost) -> 0.006 efficiency
Tech 3 Mass extractor : +18 mass/s (4600 mass cost) -> 0.004 efficiency
Tech 2 Mass fabricator : +1 mass/s (100 mass cost) -> 0.001 efficiency
Tech 3 Mass fabricator : +12 mass/s (3000 mass cost) -> 0.004 efficiency.
Commander upgrades between 0.004 and 0.006 efficiency.
Mass reactor makes all others upgrades and building useless. So, in its current state, the mass reactor totaly breaks the FA balance. Because of the efficiency, If you wanna win a game you should only build mass reactor.
Maybe should you correct the Mass reactor mass cost or mass production so that it makes the others building not useless.