Well, in a nutshell it means that the yardage is not locked to a absolute 50 yard max.

Here's why. If you have been to very many tournaments, you will have undoubtedly heard talk that a certain target was past max yardage and thereby unfair. This rule allows those setting a course to utilise rangefinders, (Which have +/- accuracy standards), without the hard wall interpretation. Also, you can no longer just see a target for "maybe 48 yards", set for 50 and hold low. You need to read the target with certainty.

I hope this helps, and good luck in this years shooting.