Some of you need to study Somali history, the Akisho or Cayisho/ means in old Somali the (Cayilsan) "Fat One." Also, the other nickname of the Akisho, Gurre a nickname given to them by the Oromo, is derived from one who doesn't "hear" because they did not speak the Oromo language when they settled among the Oromo of Bale and Arsi around 1600.
HA have assimilated Akisho from what I've read but I haven't delved into that far, I highly doubt the Somali clans would assimilate Oromo that deep into their territory, they live in Gabiley and Wajale from what I recall, the dir that live deep into Western Hararghe have been partially assimilated, I have family living in Chiro still who are Gadabuursi and still speak Somali, so not everyone has been assimilated and they have been living there for the past few hundred years alongside Ittu Oromos who are become Muslim due to the local Somali influence.
Similar to the Garre, the Madawayne branch travelled deep into non-Somali territory for trade and some got left behind and assimilated.