If you check Always Calculate, the Library Surface Speed and Library Chip Load set the Surface Speed and Feed Chipload to the same values. If you do not check Always Calculate, you must click the Calculate Now button to update Surface Speed and Feed Chipload to the same values.
To see where the Library Surface Speed comes from, click the Select Material button, and then click the Edit and Save Current Record button. There you see the surface speed values assigned to each tool material.