Pretty sure this is "how" splits are decided. The "why" is left for someone smarter than me.

112, 113, 114, 115 = 1. Anytime two of the three judges agree, that is the rating.

122, 123, 124, 125 = 2.

134, 135, 234, 235 = 3. The score in the middle (median) determines the rating.