MRP Run error " Schedule Lines not generating properly"
I am facing a typical issue with MRP Run.
Every time when I am running the MRP for a particular material I have made settings such that Schedule lines to be generated by maintaining the Source list and MRP relevancy as 2 in source list. Also I have fixed the vendor. Now my problem is I am getting Schedule lines for first run and Combination of Purchase requests and Schedule lines or only PRs for the next MRP run.. This is keep on repeating in such as way that the planning is shifting as said above for subsequent MRP Run.
Note that the initial settings during MD02 remain same for all run.
I want only schedule lines to be generated but not PR.
Pls advise and provide input where the wrong might be.
Quick responce would be appreciated.