What's the use of the 4 outputs of a power entry module (Qualtek 864-10/009), and how to interpret it's circuit digram?
With the switch as shown, the two transformer primary windings are in series, for 230 volt operation

With the switch in the "up" position, the two  primary windings are connected in parallel, for 115 volt operation.

The transformer primary windings are each designed for 115 volt. If you only used one winding for 115 volt operation, you would be limited to the same primary current as for 230 volts, so the power capacity at 115 volts would be 1/4 of the 240 volt rating (power goes by the square of the voltage).