Harold Kestenholz
Flow is a result of the force of liquid against the resistance of the pipe. If the pipe after the reducing valve is increased in diameter to accomodate the flow rate of the higher pressure liquid through lowering the total resistance, the flow might approach the flow rate in the smaller input line less the resistance of the reducing valve.
If the resistance of the initial line is reduced through partial substitution of larger pipe, the flow may equal to or may increase with the same liquid moving force. The effect is also dependent upon whether the incoming liquid flow rate is fixed or might increase due to a lowered total resistance.
