I read this rule, and chose to ignore it. In 1st edition, which I played for years, missle troops were to powerful. There were several reasons for this:
1. only 2 "ranges". this problem has been solved in the second edition, IMO.
2. Being able to shoot from wait. This has also been solved in the 2nd edition by having the troops role LD in order to shoot, and then applying a -4 to the role. IMO this is a little over the top. It should be one or the other, but not both.
3. Point cost compared to other models. In the 1st edition, most warbands were more expensive when compared to missle troops. In 2nd this is not the case.
4. There was no "run" in 1st edition. The adition of RUN helps other models avoid alot of exposre to missle fire and HOA. This helps limit them nicely, and forces the player to really think when using missle troops.
5. Damage in 1st edition was higher for arrows than in 2nd. This is pretty self-explanitory.
IMHO I think that this rule is completely unneccessay. I think quite a bit has been done to rein in missle troops, especially bowmen. I would not use this rule unless I played in a tournament setting and everybody wanted to play this way. If this were the case I would play a force without bowmen. Unfortunately. several armies in the game, due to their construction, need missle troops to help them out. I think punishing them is unfair.