You can't go using the term Ackerman loosly... there are too many cases. Generally you are correct... for straight run cables. You want no offset,or you may want to error slightly on the side of the control horn being behind the hinge line.. this causes the cable to loosen slightly when deflected.

We were talking about crossed cables in previous posts. They loosen when deflected if offset is not used. You WANT an offset that will take up the slack when deflected... hence a servo arm with offset toward the tail. Millions of flyers and companies can't be wrong!!! Another way to take up the slack would be to set the control horns so they are in front of the hinge line, but this is not practical because they will hit the fuse before they reach full throw... not a good practice.

TEST out the formula above... it works. Don't use someone's opinion as a basis for arguement. I don't want this thread turning into the crystal taping thread or EF Yak threads. 'Nuf said.