Thanks for your comments, txstamp - I'm feeling better all the time that I made a wise purchase.
It's interesting to me that 89R2, while just as rare, is worth a just a small fraction as much as 99R2. I know 89R2 is a #7, but it would seem it should have as least some of the same kind of notoriety 99R2 has. Neinken, after all, wrote that it is the a "stamp showing the most pronounced double transfer, or reentry, on any U.S. stamp". I feel lucky to own a nice fault-free example of both.