Nāmarūpa as the object of consciousness seems only found in the suttas which omit sankhara & avicca. 
omits & alternately defines a number of conditions. Personally, I avoid doing what Nanananda did, which was to impute DN 15 onto SN 12.2. DN 15 seems not found in the Patisambiddha Magga or the Abhidhamma. It seems DN 15, during that era, did not have the same esteem as Theradava has given to it in more recent times. I suggest to consider Sujato’s introduction to the DN. The Long Discourses: Dhamma as literature and compilation 
If DN 15 is emphasized, then the six-fold consciousness is overlooked. 