Okay I decided to play along and see what would happen - I had a hotel I needed to book for next week. Nowhere does it say this until the confirmation email, but the language in that email suggests the difference between "base miles" and "promotional miles" - my suspicion is that my additional 2,000 miles will not qualify as LP's.

While I'll still have the benefit of the extra 2,000 miles from an RDM perspective, I doubt I will continue to book these "promotional miles" rates unless we get confirmation they will count as LPs.