“Now, the phrase “@ëlleh thôlëdôth” occurring only five times and only in Genesis begs the question of why its usage was so limited, but I’ll address why I think this happened in another post given the wording. in the Masoretic.” (From “On the Generations Of: A Pattern of Usage”)
So, why do I think Scripture uses “@ëlleh thôlëdôth” only five times? Because I think the phrase was used to identify five writings Moses used to compile the book of Genesis, telling the Story of the Line of the Promise from the rehabilitation of the earth to the death of Jacob. A sixth scroll written in Egypt continued the Story through the death of Joseph and ended the book instead of using the signature phrase. I think these five writings were preserved in the Line of the Promise down through the generations with Jacob bringing them with him to Egypt.
So, here’s the intro of the essay that I wrote discussing my research and 
conclusions.
Grace and peace to you,
Dori