Well your first post said the table was level when the mechanic left, and got unlevel 2 hours later, due to settling.
Your next post to me said the table was never leveled when the mechanic was there, and you didn't notice until immediately after he left. That's very different than your first post.
If the second is true, then it seems the mechanic did a poor job all around, and its very likely the slates are all messed up, and would need to be individually adjusted at the leveling screws underneath each slate.
If the first is true, then that's most likely settling, which can probably be fixed with the legs only.
Still, you have nothing to lose at this point moving the legs, IMO. Ps, I'm not a mechanic, just a player with a table and level myself.