I wonder if the recent success of our defense, attributable primarily to the defensive line, has altered Whaley's philosophy. By grabbing someone upper tier like Iupati, he would be building an offensive line as a strength of the team, much like the defensive line. Perhaps that is the philosophy that Rex brings that Whaley is on board with: build powerful offensive and defensive lines, and the rest will follow.
Of course, if we can get a talented second-tier guy for less who is almost as good, I could see that. But I would like to see them spend the bucks on the line players (Iupati, Hughes) before guys like DBs.