More specifically, notice that the "big arms" don't start their pull forward until (or just after) they plant their front foot. At this point their shoulders are fully turned away from the target (I know it's hard to trust this at first when you eyes are pulled off your target), and you can just about draw a straight diagonal line from their front foot, up their leg, up their spine, through their head. From here, they pull forward with their legs and hips first, forcing the upper body to uncoil only after the hips are already turning. This keeps your spine "loaded" for longer, and allows the weight transfer to come later in your pull, creating that great "whipping" action that Beato and others describe as late acceleration. This was one of my own personal "aha" moments, because left to my own devices, I had been starting my weight transfer just before I planted my front foot, which throws off the whole flow. I think you're making the same mistake.
