1/2" can make a difference, as can bending your elbows a little more. Keep riding it like that for a few weeks to make sure it doesn't cause any pain. At that point, you can go lower if you desire (if you're out of spacers to remove, get a stem with a lower rise), and when you're absolutely sure that you found the height you want, you can take it to a shop to have the excess on top cut off (leave 1 small spacer on top if you have a full carbon fork).

fwiw I can only get about 2" difference between my saddle and bars, but I can get my back as low and aerodynamic as anyone else. It's different for different people.