They move up and down with the freeze thaw. Tie your deck into the house at one level only the ban board of the deck to the house. Also if you are putting on a handrail dont tie it into the house let it move with the deck hold it off the house a inch should be sufficient. I wouldnt use themin a area i new was going to be wet or muddy for prolonged periods.
Thats what we are doing now. Putting a 38x17 deck off the back. Heave does mean move with the freeze/thaw. We dug the holes also. We rented a hydrolic auger from Home Depot and it worked great! One man can dig the holes with this thing. We are not attaching the deck as it will be free floating. Meaning it is not attached to the house. We lade out a hole every 8' and 36" deep. Well one we hit a big ass rock so it is only 26". I was not digging the rock out. lol