That theory would make sense if Aidid was sent to the front lines, but him and the Galaal dude in the video were military administrators at the presidential office during the war and after the war he was sent as ambassador to India. Yey, however, was leading from the front lines and this is what the Ethiopian General who faced Yey's men on the other side had to say in his autobiography.
http://www.demissiebulto.com/
I think the Ethiopian general is describing the retreat of Somali army because awassa is like 250 miles from Ethiopia.
As for the topic, I don't believe the 95% deal. There are records of Soviet leaders telling Siyad, they would side with Ethiopia. He might have hoped for US support, because he knew Soviets would side with Ethiopia, but they too sided with Ethiopia. I do believe Siyad was honest in his quest for conquering the Ogaden.