Until now, the start of activities for 3rd generation members was the 17th single “Influencer” (“Sanbanme no kaze” included as coupling song), but this has been changed to the 18th single “Nigemizu” (first senbatsu for Ozono Momoko and Yoda Yuki).
The main reason for the change is that the start for 2nd gen members is the 7th single “Barrette”, in which Hori Miona was senbatsu for the first time, and the start for 4th gen members is the 24th single “Yoakemade tsuyogaranakutemoii”, which saw Endo Sakura chosen as senbatsu for the first time. So it would make sense for the same logic to apply to the 3rd generation.
This change results in higher senbatsu averages for 3rd gen members and affects the senbatsu average ranking. For example, Yoda Yuki’s senbatsu average has changed from 11/13 = .846 to 11/12 = .917.