Transfer Orders

Hi,

I am using JD 9.1. i am making transfer order. For transfer order , we need to activate it through processing options of P4210 Transfer tab. By this automatically purchase order will be made.

So my question is if we want to generate a purchase order do we need to activate the flag ( generate Purchase Order) in line type constants.

In my project we are using line type S for which flag is not active, only processing options of P4210 is put to 1 and still PO is made.

So if it is made without activating the flag in line type constants, what is its use?