My Aquis with the Sellita SW200-1 runs -11 a day.
What position do you rest it?It is positional variance you are experiencing which is not uncommon. Do you know how old your watch actually is? I didn't see that in your original post. If it's over four years old and was worn often by the original owner, it may benefit from a service which would include a regulation. If done right, you should see an increase in accuracy all around.