I am a big fan of the chain knot. Thats what we used to call that same extention cord stowing method. Also great for stowing long pieces of webbing.
At work now we stow some very long length 1/2" diameter rope. But we stuff it in rope bags. Which is literally a canvas bag with a grometted hole in the bottom. To use us, you simply thread the end of the rope through the grommet in the bottom of the bag and tie a stopper knot outside the bag. Usually a figure 8 or overhand knot. Then start stuffing the standing part of the rope into the bag. As long as you keep the working end of the rope outside the bag......believe it or not, it will pay out from the bag every single time. Because no matter how many bights of rope are in there, without either end in the bag, it wont knot up.