I am trying to make myself more compact at the moment. More so with my right hand. I have a bad habit of letting it go from about 3 cm from the right side of my head rather than straight from my face.

However, for me I think this probably makes the punch slightly longer because it's more direct and my elbow stays in more.

Are you sure he actually wants you to punch shorter or do you just feel you're not getting the body rotation in?