NZGS Interim Guidance on Retaining wall design – load factor changes  

I was interested to read the new interim guidance on retaining wall design which modifies the dead and live load factors to be used for the static case in Module 6.

I remember when Module 6 came out many of the engineers in the office were surprised to see such a low load factor for Q for the static case. Whilst I am not a Geotech, I understood that the static case in the guidance was intended to represent a “drained soil case” where the footing was exerting pressure on the founding soil for a long period of time. In this context, the use of a live load coefficient of 0.4 was in line with the use of a long term live load factor, ψl. So it made sense to me in that way.

I guess I’m just thinking that the original guidance would not have contained such an obvious flaw without some kind of rationale to justify it. Wondering what others think about this one.