Avatarika
एवं तावत्पुरश्चरणान्तर्गतप्रणवमात्राव्यूहोपासनमभिधाय इदानीं सामाभिव्यक्तमूलमन्त्रेण ब्रह्मोपासनामभिधातुं मूलमन्त्रस्य प्रणवसम्पुटीकरणादक्षरसंख्याविवृद्धे. कथं द्वात्रिंशदक्षरं सामेत्याशङ्क्य पादशः पञ्चाङ्गन्यासं च अभिधातुं पादाक्षरसंख्यापूर्विकां कृत्स्नमूलमन्त्राक्षरसंख्यामाह—
In plain words
So much, then, for the meditation on the array of the Praṇava's moras, folded into the preliminary practice. Now the real work begins: showing how the root mantra, once voiced through the Sāma, becomes a meditation on Brahman itself. But a question arises first. Fuse the Praṇava into the root mantra, and the syllable-count grows -- so how can this still be called a thirty-two-syllable Sāma? That doubt has to be faced before anything else. To answer it, and to lay out the fivefold placement of limbs quarter by quarter, he first gives the total syllable-count of the root mantra, building up from how many syllables fall in each quarter.
Close to the Sanskrit
Thus, having first described the meditation on the array of Praṇava-moras included within the preliminary practice, now, in order to describe the meditation on Brahman by means of the root mantra as manifested through the Sāma -- there being, because of the interlocking of the root mantra with the Praṇava, an increase in the count of syllables, [raising the doubt] 'how can the Sāma be said to be thirty-two syllabled?' -- having raised this doubt, and in order to state, quarter by quarter, the fivefold placement of limbs as well, he states the total number of syllables of the root mantra, prefaced by the count of syllables per quarter.