I don't know if I'm buying you get less nodes if the plant streches. Yes, if the plants were equal sizes and one had nodes every inch versus one that had nodes every 3 inches, you would expect more bud from the one with nodes every inch. However if two plants grown the same amount of time, one just happened to stretch, I believe they would have the same amount of nodes, one just has them more spaced out. In-fact I get slightly more bud off my slightly stretched plant because my setup is able to light the inside buds of the plant better.
Your plant was probably just starving for light after being vegged under 1 X 13 watt CFL for a month. Also most root growth happens during dark so I recommend you veg at 18/6 next time. Once the plant got more light, and some darkness to grow better roots, the thing probably just took off like rocket.