The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
27. The objection that (the Brahman of the former passage cannot be recognised in the latter) on account of the difference of designation, is not valid because in either (designation) there is nothing contrary (to the recognition).
The objection that in the former passage ('three feet of it are what is immortal in heaven'), heaven is designated as the abode, while in the latter passage ('that light which shines above this heaven'), heaven is designated as the boundary, and that, on account of this difference of designation, the subject-matter of the former passage cannot be recognised in the latter, must likewise be refuted. This we do by remarking that in either designation nothing is contrary to the recognition. Just as in ordinary language a falcon, although in contact with the top of a tree, is not only said to be on the tree but also above the tree, so Brahman also, although being in heaven, is here referred to as being beyond heaven as well.
Another (commentator) explains: just as in ordinary language a falcon, although not in contact with the top of a
tree, is not only said to be above the top of the tree but also on the top of the tree, so Brahman also, which is in reality beyond heaven, is (in the former of the two passages) said to be in heaven. Therefore the Brahman spoken of in the former passage can be recognised in the latter also, and it remains therefore a settled conclusion that the word 'light' denotes Brahman.