Cheek weld matters, comfortable cheek weld. Not everybody's cheek is created equal. To say it is best to mount the scope as low as possible isn't always right, if you can't comfortably get behind it. There is nothing wrong with a high mount, provided you get a solid cheek weld, and if you subscribe to the PBZ method of zeroing, a higher mount will extend that distance a little. If you shoot prone a lot, you might find a lower scope height to be more comfortable and easier on the neck. Sitting at a bench or standing it really isn't an issue, again, as long as you have a good cheek weld.