Parson has, indeed, weasled his way out of Stanley's orders, by nature of their wording: remember where Stanley said "Shut up! Shut up until you're ordered to speak!"? Stanley never specified who could order Parson to speak again, so Parson attempted to have Bogroll (unsucsessfully) and then Sizemore. So it is shown that Parson can take Stanley's orders as literaly as he wants to.
Wanda said: "Commander Parson, if you refuse an order, the spell which summoned you will end your existance entirely. You must serve your Lord's will and desires. Forever." So, we do not know if Parson must only obey orders given by Stanley, orders given by any lord under whom Parson serves, or if he must obey any order given by anyone.