The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
6. Not to one (element) (the soul goes); for both (i.e. scripture and Smriti) declare this.
At the time of passing over into another body the individual soul does not abide in the one element of heat only; for we see that the new body consists of various elements. This matter is declared in the question and answer about the waters called man (Kh. Up. V, 3, 3); as explained by us in III, 1, 2.--Scripture and Smriti alike
teach this doctrine; compare e.g. 'Consisting of earth, water, wind, ether, heat' (Bri. Up. IV, 4, 5); and 'The subtle perishable parts of the five (elements) from them all this is produced in due succession' (Manu I, 27).--But is there not another scriptural text--beginning--'Where then is that person?'--which teaches that at the time of the soul attaining a new body, after speech and the other organs have been withdrawn within the soul, work constitutes the soul's abode, 'What those two said, as work they said it; what they praised, as work they praised it' (Bri. Up. III, 2. 13)?--That passage, we reply, describes the operation of bondage consisting of the senses and their objects--there called grahas and atigrahas--and therefore work is spoken of as the abode; here on the other hand the elements are said to be the abode because we have to do with the origination of a new body out of the matter of the elements. The expression 'they prayed' moreover intimates only that work occupies the chief place in the process, and does not exclude another abode. The two passages therefore do not contradict each other.