I just finished re-reading War Room and I think it's obvious he does put a lot of weight into perceived market value, if for no other reason than it creates scenarios where he can get additional value out of trades. We have a book on every team and their needs and BB includes that info when he's jumping around the draft board. Those books get updated throughout the draft as well now that it's broken up into 3 days. So it's not correct to assume he doesn't care at all about perceived market value.
I think what many of the draftniks (and fans) are overlooking is another thing related to economics, which is trends. He talked about how Vollmer's tape really only justified a 4th or 5th pick, but they felt he was definitely moving up in the process on other team's boards. so you either take him earlier than the tape says or risk losing him.
I don't know the whole story on Jordan Richards, but I don't think it's enough to just look at a bunch of draftnik websites and see their projections. It misses a huge part of the story, which is the movement which can occur before the draft from visits and interviews and tape breakdowns with coaches that we don't get to see, but play a huge role in the evaluation. It can also happen during the draft due to a run on the position, or a team's other potential targets being drafted so they look further down their needs list.
In the book, BB talks a lot about this process. It's really interesting and insightful in how his mind operates during this process and I'd highly recommend it.