Help with Backing Up

I do all the driving of our big rig. But when we get to our destination, I hop out and DH does the parking/backing. Sure, I can do it, but it takes longer. He said it's because I give better, more understandable hand signals than he does. He is dyslexic and that may have something to do with it. We use totally silent hand signals. . . I know how to keep in his line of vision and it's pretty much flawless when we do it. No yelling, screaming, or radio noise.:C

Dale