That's how I used to get my self into position. I would dip my knees and hips a bit to get into extension and then squeeeeeze myself back into starting position. Activating the lats helps keep the bar where it supposed to be.
I stopped doing it that way because I have been learning the SS way. Dropping the hips tends to knock the bar out of place so instead you're supposed to get into extension by "squeezing " the chest open and into place.
I'm doing it this way because of the upcoming cert. but I don't see whats wrong doing it the other way as long as the bar is in the right position when you lift it. Anyone?