This is an old argument - Move a half run or move juice. As a player who is not a scalper I would prefer the extra half run. Of course you can always look for books to move one run or more and if you had the forsight to bet over/under the right way when the number was posted, you can find yourself with a nice middle.
As to which way is better bookmaking, I believe it is a close call, and really up to the books style of operating. I remember the Horseshoe would never move off a number on Cub games at Wrigley, they simply would keep moving the Juice. Sometime you could end up seeing 11 over -165 if the wind was blowing out. Other books like the Stardust for example would have the same game 12.5 flat.
wil.