you can enter the value much more precisely than it is displayed. you can click on the dial and enter:
"0.47 h" and it will be "translated" to 0.47 Hz on the dial. you can even enter 0.477 h and it will be translated to the corresponding value. (you will not see this in the ui, but the value is much more precise than what you see)
you can also use shift drag to drag more precisely...