I heard from a good source that the zone where you can have a legitimate shot at making the putt is up until 12 feet. After that, your odds decline, but not in a linear fashion versus length. For example, you have more or less the same chance of making a 25 footer as a 40 footer. So the point is that you should practice putts inside of 12 feet since those are the ones you have the best chance of making consistently. Is this true?