Hi, I've got several building at level 1 right now, and I try to updgrade them at level 10 to slightly increase my production and have the achievement. But I've notice that when I reach a certains level, my production starting to decrease a lot! For exemple if I upgrade my times machines to level 1 to 10 it increase my production a little, but if i go until level 16 my all production per second is divided by 2! How could that possible??