Only watched a minute or so of each, but not too bad.

By square, he means your upper body. Your feet may be back, but your rear shoulder is forward, squaring off your shoulders with the bag. This makes your jab have a bit more umf, but your "rear" hand loses power, and makes you a much bigger, easier to hit target.

Also, you almost seem to have a thai boxing stance, as opposed to a traditional western boxing stance. Your rear hand is high, palm outward (unless the glare is really messing with my vision, which is possible).

Not bad overall, and definately an improvement. Keep up the good work.