In the Pali Tipiṭaka it’s mentioned in only two places: the detailed description in the Paṭisambhidāmagga’s account of a Tathāgata’s asādhāraṇa accomplishments (i.e., those which are not shared by his arahant disciples), and then a passing mention of it in the Niddesa.
In academic Buddhist studies the term ‘paracanonical’ is usually applied to the Nettipakaraṇa, Peṭakopadesa, Milindapañha and (sometimes) the Suttasaṅgaha.
I’m not personally acquainted with any Buddhist canonical community that regards the Paṭisambhidāmagga as paracanonical. If the canonical community is the theras of the Mahāvihāra and their heirs, then the Paṭisambhidāmagga is impeccably canonical, being regarded as the work of Sāriputta. If it is the community of those who subscribe to modern scholarship’s assessment of which Pali texts are early, then the Paṭisambhidāmagga would usually be viewed as a late addition to the Khuddaka Nikāya and therefore non-canonical.
Yes, it’s usual for the Dhammapada Commentary’s account of something to be rather more grandiloquent than the same thing described in the Suttas. This is the Paṭisambhidāmagga’s account:
THE TWIN METAMORPHOSIS (MARVEL) ]
What is the Perfect One’s knowledge of the Twin Metamorphosis (Marvel)?
Here the Perfect One performs the Twin Metamorphosis (Marvel), which is not shared by disciples.
He produces a mass of fire from the upper part of his body and a shower of water from the lower part of his body: he produces a mass of fire from the lower part of his body and a shower of water from the upper part of his body. He produces a mass of fire from the east side of his body and a shower of water from the west side of his body: he produces a mass of fire from the west side of his body and a shower of water from the east side of his body.
… from the right eye … left eye … from the left eye … right eye …
… from the right ear… left ear…
… from the right nostril… left nostril…
… from the right shoulder… left shoulder…
… from the right hand … left hand…
… from the right flank… left flank …
… from the right foot… left foot…
… from each finger and toe … each space between the fingers and toes…
He produces a mass of fire from each hair and a shower of water from each hair: he produces a mass of fire from each hair’s pore and a shower of water from each hair’s pore.
Amid the six colours of blue and yellow and red and white and pink and transparent the Blessed One walks while his created image stands or sits or lies down, the Blessed One stands while his created image walks or sits or lies down, the Blessed One sits while his created image walks or stands or lies down, the Blessed One lies down while his created image walks or stands or sits, the created image walks while the Blessed One stands or sits or lies down, the created image stands while the Blessed One walks or sits or lies down, the created image sits while the Blessed One walks or stands or lies down, the created image lies down while the Blessed One walks or stands or sits.
This is the Perfect One’s knowledge of the Twin Metamorphosis (Marvel).
(Ñāṇamoli, Path of Discrimination 126-7)