Steering Clocking suddenly off ...

I am throwing darts here, but usually what you are describing seems like bent components after hitting something. You say it happened after parking the car so that eliminates hitting something with the front suspension components. I would shake down the front end, at this point I am suspecting the steering box, I may be wrong, its just a guess.
that was my first thought as well. I'm wondering if one of the older components sprung from sitting with the wheels turned and the steering wheel locked on the hill. I've actually had this happen on an old John Deere 4440 after leaving it sit all winter with the wheels turned. But that was for 2 months. not a couple hours.