The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
21. (These details) are recorded by Smriti with reference to the Yogins; and both (Sâṅkhya and Yoga) are Smriti (only).
The rules as to dying by day and so on in order not to return are given by Smriti for the Yogins only. And those two, viz. Yoga and Sâṅkhya are mere Smriti, not of scriptural character. As thus it has a different sphere of application and is based on a special kind of authority, the Smriti rule as to the time of dying has no influence on knowledge based on scripture.--But, an objection is raised, we have such passages as the following one, 'Fire, light, the day, the light half of the month, the six months of the northern progress; smoke, night, the dark half of the month, the six months of the southern progress' (Bha. Gîtâ VIII, 24; 25); in which though belonging to Smriti we recognise the path of the gods and the path of the fathers just as determined by scripture!--Our refutation, we reply, of the claims of Smriti applies only to the contradiction which may arise from the teaching of Smriti regarding the legitimate time of dying. 'I will tell you the time,' &c. In so far as Smriti also mentions Agni and the other divinities which lead on the departed soul, there is no contradiction whatever.