Obviously if some libraries use less precise information matching and de-duplicating can also be less precise. However, the totality of the information that you have, meaning some information from different sources, can be used to make sense of things. So if MOST libraries have stated that the title page title is "Title X" then you can assume that an undifferentiated title "Title X" is a title page title. It's not a 100% kind of match any more, but a more nuanced match (that Simon probably has the correct terms for!). The Open Library used a version of this in their determination of Works by using the information from records that did have uniform titles to bring in records for the same manifestation but that had not included the uniform title.