Different transmissions for reciting various versions of a same mantra acc. to any of Vajrayana branches Tashi delek! My question concerns the mantra reciting in Vajrayana tradition, where some Buddhist deities (not to be confused with the mundane ones) may have several versions of a same mantra. 

That is, a mantra of a same deity may be either longer or shorter according to different sutras and dharanis.

In Vajrayana, it is also very important to receive a direct transmission of energy from guru (lama) before reciting any mantra.

My question is, can a Vajrayana practitioner recite another version of the same mantra if she or he has already (in a given reincarnation) received from her or his guru a transmission for receiting another version of the same mantra?

A reference to any root texts of any Vajrayana branch (Gelug, Sakya, Nyingma, Kagyu or Jonang) would be a great help.
This is a very partial answer because I can provide no textual reference.

Differences between mantras of the same deity are of two types:


In terms of length (short version / long version)
In terms of category


For instance: Vajrasattva has (1) a short mantra, (2) a long mantra, and (3) a mantra associated with its wratful aspect, that is another category, such as 'Heruka Vajrasattva'.

Generally, there is no objection for practitioners who received an initiation to recite both short and long version of a mantra of the same deity. As to reciting the mantra of another category/aspect of that same deity (in the given example, that of Heruka Vajrasattva), you must ask your teacher. In Kopan monastery - and so Kyabje Lama Zopa Rinpoche - they do allow one to recite Heruka to those who took just Vajrasattva. If you are not a student of his, ask your own teacher.