The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
5. In the case of (a devout meditation) common (to several Sâkhâs) (the particulars mentioned in each Sâkhâ) have to be combined, since there is no difference of essential matter; just as in the case of what is complementary to injunctions.
[This Sûtra states the practical outcome of the discussion carried on in the first four Sûtras.] It having been determined that the cognitions of Brahman are equally intimated by all Vedânta-texts, it follows that as long as the cognition is one and the same its specific determinations mentioned in one text are to be introduced into other texts also where they are not mentioned. For if the matter of these determinations subserves some particular cognition in one place, it subserves it in another place also, since in both places we have to do with one and the same cognition. The case is analogous to that of the things subordinate to some sacrificial performance, as, e g. the agnihotra. The agnihotra also is one performance, and therefore its subordinate members, although they may be mentioned in different texts, have to be combined into one whole.--If the
cognitions were separate, the particulars mentioned in different texts could not be combined; for they would be confined each to its own cognition and would not stand to each other in that relation in which the typical form of a sacrifice stands to its modifications 1. But as the cognitions are one, things lie differently--The above Sûtra will be explained and applied at length further on, in Sûtra 10 ff.
192:1 The Pûrvâ Mîmâmsâ teaches that all subordinate things which the Veda prescribes for some typical sacrifice are eo ipso prescribed for the modified forms of the sacrifice also.