The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
12. For this reason Bâdarâyana (opines that the released person is) of both kinds; as in the case of the twelve days' sacrifice.
The teacher Bâdarâyana, again, thinks that for this reason, i.e. because scripture contains indications of both kinds, the proper conclusion is that the released person exists in both
conditions. When he wishes to have a body, he appears with one; when he wishes to be disembodied, he is without one. For he has various wishes, and all his wishes are realised.--'As in the case of the twelve days' sacrifice.' As the soma sacrifice extending over twelve days may be viewed either as a sattra or as an ahîna sacrifice, because both alternatives are indicated by scriptural passages 1; so it is here also.