I use olive oil on my hair everytime I do Braidouts, that and some other oils.
I dont apply it to the deep conditioner, BUT I do add it to my hot oil treatment, which is home made
I like the way it leaves my hair, soft managable, and give it shine without weighing it down.
I dont know if it is due to the olive oil, because I use other prodcuts also, but it might be it!