I'm with you here Jondamon. Most people neglect to account for the transitional phase of the plant growth. I've had this discussion with sooo many people, and it often turns into a big thing. I really think its one of the biggest reasons people cut early, and aren't happy with their final outcomes. You constantly see people on here asking if their plants are done at "7-8 weeks of 12/12", when they clearly need more time.
To the OP, the simplest explanation for why the yield was poor on your buddies plants, and if it ends up poor on yours that are the same genetics, would be genetics. Even with all the other possible variables, including being cut early perhaps. If the phenotype of those genetics you have is a light yeilder, then end of story really.
As far less is more.... I run a single cola SOG. My plants get a week or 2 of veg after being cloned and put into pots, and are usually about 6-8 inchs tall when I flower them. Because the genetics are mature they take about 7 days to actaully start forming flowers, and continue to stretch a bit for about 5-7 more days before they really settle into making buds. I typically start "counting"(I don't really count any more, just harvest whats ready when its ready) once the plant actually starts forming flowers. I consider this to be the beginning of "flowering".