Shortening the hair is preferred for the one performing tamattu'

O Shaykh, may Allah reward you with good, regarding the one performing tamattu': Is it preferred for him, when exiting the state of ihram, to shave his head, or to delay shaving and shorten his hair?
It is preferred for the one performing tamattu' to shorten his hair; because this is what the Messenger (peace and blessings be upon him) commanded,He said: (then let him shorten his hair and exit the state of ihram), and because if he shaves and the time for Hajj is near, nothing will remain for Hajj.