Okay, so 6 prod and 6 food difference until you have upgraded terrascapes (which are 3/3/3 and ignore base yield). Let's say in 150 turns that is a 900 prod and 900 food yield. This of course demands that you tech according to your starting position, but I said that already. Compare that to what could be 15,000 beakers with a full game's access to old AB.