Just a thought, if you are instructing IMC and you are in imc condiions i take it this fliht time can be logged as flown by sole refference to the instruments, and since you are instructing you are the PIC, i take it you should log it as such, and wether you are or not touching the controls is irrelevant from my point o view.
otherwise no instructor should log any flight time at wich he instructing but is not handflying himself, it is just nonsense.