… some groups of suttas in the Aṅguttara Nikāya with saṃyutta-like nature were probably moved from the Saṃyutta Nikāya to the Aṅguttara Nikāya within the Pali tradition. Evidence of a comparable movement into the Ekottarika Āgama is also available.
In the Ones and Twos, it is often the case that a single original sutta has been subdivided so that its component sections become a series of similarly structured derivative suttas superficially appropriate for inclusion in the Ones or Twos. Moreover, material for this process of subdividing has sometimes been provided by multiplying doctrinal sets with formulaic statements.
On how the AN/EA was originally composed and subsequently grew and developed (in response to the needs of the recitation groups).