D'OH!
Now that you point that out, I realized something I was overlooking. On page 3-4 of Crane is the note:
"The values of the resistance coefficients (K) in equations 3-17, 3-18, and 3-18.1 are based on the velocity in the small pipe. To determine K values in terms of the greater...
It seems to me that most of the loss information contained in Cameron Hydraulic Data manual is derived from Crane's Technical Paper #410: Flow of Fluids through Valves, Fittings, and Pipe. For example, the table on page 3-120 of Cameron uses the K-values from Technical Paper #410 with a...