Vishnu,
I have never seen a Manufacturing manager that would accept that the dates in his production orders would change after every MRP run.
I have never seen a Buyer that would be willing to call the Vendor after every MRP run to inform him that the dates on his Purchase Orders had changed.
I suppose your client might have a direct line to his CEO's office, because it would take that kind of pull to get that policy implemented in any company I have ever seen.
Best Regards & Good Luck,
DB49