The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
30. On account of remembrance; so Bâdari opines.
Or else the highest Lord may be called 'measured by a span' because he is remembered by means of the mind which is seated in the heart which is measured by a span. Similarly, barley-corns which are measured by means of prasthas are themselves called prasthas. It must be admitted that barley-grains themselves have a certain size which is merely rendered manifest through their being connected with a prastha measure; while the highest Lord himself does not possess a size to be rendered manifest by his connexion with the heart. Still the remembrance (of the Lord by means of the mind) may be accepted as offering a certain foundation for the Sruti passage concerning him who is measured by a span.--Or else 1 the Sûtra may be interpreted to mean that the Lord, although not really measured by a span, is to be remembered (meditated upon) as being of the measure of a span; whereby the passage is furnished with an appropriate sense.--Thus the passage about him who is measured by a span may, according to the opinion of the teacher Bâdari, be referred to the highest Lord, on account of remembrance.
151:1 Parimânasya hridayadvârâropitasya smaryamâne katham âropo vishayavishayitvena bhedâd ity âsankya vyâkhyântaram âha prâdeseti. Ânanda Giri.