https://www.nclhltd.com/news-media/press-releases/detail/553/set-sail-and-receive-simply-more-oceania-cruises-new
You are so correct! Comparing sale fares without knowing the non-sale fare does not give a true indication of the effect of SimplyMore.
From my analysis of Alaska cruises, NON-sale cruise-only plus Olife fares increased by the difference between the Olife OBC and the SimplyMore OBC (e.g., was $300, now $400 so $100 increase). Airfares for <~13 day Alaska cruises increased $100.
To see my reasoning (post #43)...