There is definitely a difference when you get off the bench and start using other positions. And, for most field shooting (at least around this area) the prone is the least-likely position you'll use. Simply too much vegetation to see down range. But, I'm always just 16" from a kneeling shot, and I'm often within a step of a hasty rest in the form of a sapling.
These days I use the bench for zeroing and teaching grandkids, but after I've zero'd I get away from the bench and try to concentrate on shooting as I would in the field. As a hunter, for example, I spend time in my stand, so I try to duplicate the conditions I have in my stand for my practice shooting. For true field shooting I know the vital area of my target and I try to make sure that I can put the bullet into the vital area every time. My current standard is to be able to whack a 9" plate at any distance I might see game. I use the 9" plate because that approximates the vital area of a standard whitetail deer.
Now, a 9" plate at 300 yards is 3 MOA, which isn't a terribly exacting target if you're used to sitting at the bench and shooting at tiny targets, but once you get away from the bench and start trying to hit that 9" plate in real-world conditions, it becomes a challenge.
Keep shooting, keep practicing, and try to learn something from every range outing.