Wouldn't the magic number be a 42mm chainline? Pull the cranks off and see how smooth the bottom bracket spindle moves. Once, when my bb was seriously bound, it still spun freely because of the momentum of the cranks, but when I removed the cranks it was obvious that it wasn't working properly.

Is it possible that the lockring on the bottom bracket wasn't on as tightly as it should have been? Once the cranks are off, you might have to re-adjust the bottom bracket and re-torque the lockring.