In this statement, Ven. Yin Shun suggests:
Even if the original form of SA/SN is being considered the most ancient/earliest, it does not mean one is able to understand SA/SN is a synthesis of the three parts/aṅgas (sūtra, geya, vyākaraṇa). Without knowing the characteristics of the three aṅgas and their connection with the formation of the other three Agamas/Nikayas (MA/MN, DA/DN, EA/AN), it is impossible to understand the process of forming the four Agamas/Nikayas according to SA/SN.