He’s contradicting himself. In his book he lists the Atthakavagga as being earlier than the DN, MN, AN, and SN. This is consistent with with the consensus of scholars who use the list compiled by Rhys Davies who’s list he uses in his book. @sujato says what he would change on that list and moving the Octads/Atthakavagga is NOT one of them.
![](https://discourse.suttacentral.net/letter_avatar_proxy/v4/letter/r/35a633/48.png)
This is obviously meant as a simple aid to orientation among the material, not as definitive or exhaustive. In an excellent example of the friendly and critical debates that characterised this period of early Indology, the list was swiftly criticised and nuanced by Bimala Law [4, ch. 1]. Nevertheless, if we allow for the limitations of such a simple presentation of such a complex subject, his sequence holds up very well. The main changes we would suggest is to place the Itivuttaka with the Udāna and other texts at number 5, and to allow that the Abhidhamma was compiled alongside the other texts, probably from number 6 on, or at least from number 8.