The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
5. On account of the difference of words.
That which possesses the attributes of consisting of mind, and so on, cannot be the individual soul, for that reason also that there is a difference of words.
That is to say, we meet with another scriptural passage of kindred subject-matter (Sat. Brâ. X, 6, 3, 2), 'Like a rice grain, or a barley grain, or a canary seed or the kernel of a canary seed, thus that golden person is in the Self.' There one word, i.e. the locative 'in the Self,' denotes the embodied Self, and a different word, viz. the nominative 'person,' denotes the Self distinguished by the qualities of consisting of mind, &c. We therefrom conclude that the two are different.