Oh you're factoring in head movement. I see. Well you still haven't accounted for the warping that the optics do. They stretch that 1080 pixels across a 100 deg

Oh you're factoring in head movement. I see. Well you still haven't accounted for the warping that the optics do. They stretch that 1080 pixels across a 100 degree vertical field of view, so the pixels directly in your sight (not including peripheral vision) is really only about 320.