You mention you're hunched over at the line. It's possible your swing itself hasn't changed as much as your posture, which will make it seem like your swing is higher. Make sure you bend your knee to get your body nice and low at the foul line on your slide step, as well as bending your knee on your short power step immediately before your slide step. This should keep you from having to bend over at the line to get low, which should straighten up your back and lower your swing. If that doesn't fix it, we can address the swing itself then.
