Empty level has much more fps then an established level with every single sub level hidden

Im not sure this is a bug or not, but id still like an answer why…

Empty levels have much more fps then an established level with every single sub level hidden… basicly 0 drawcalls vs 0 drawcalls… yet the empty one will get 180-200 fps… while the one with every sublevel hidden will get around 120 fps…Is this normal? Why?