reservation-planning run

Dear all

when do the reservations for the dependent requirements created? Immediately after planning run for final product? or

at the time of conversion of planned order in to production order?

for all levels of bom?

If x is finished.x1,x2 are bom for x( final assy procuct )

if x1 has bom R1( to be provided to sub con vendor to prepare x1 after under going machining)

when we run planning for x

planned order generated for x

PRs generated for x1 and x2. what about purchase requisition for R1. Need i maintain any field to get PR for R1.

At the time of planning run what is the difference between

1 1 1 3 and 2 1 1 3 ie pur req in open period

How data to be maitained for all the above materials