Note that a connecting flight seems to show R[lowest R on any flight] for all flights. For example, I was looking at DEN-ORD-BWI, and the DEN-ORD 772 showed R5, as did the ORD-BWI 320. When checking the individual flights, the 772 showed R9 and the 320 showed R5. United.com did not work that way...it showed the actual availability for each connecting flight.