copying delivery time from 1st (unconfirmed) schedule line to confirmed SL

Hi Friends

Long time since I visited our forum.

During order creation or change, by selecting all items and using 'Edit- fast change of- Delivery date' menu option one can set a delivery date and time for all the items. This info moves to schedule line 1 (for the requested delivery date) Shipping tab to Arrival time field. However if an item (s) is not confirmed for the requested date, then a second schedule line is created for the confirmed date based on user's choice in the ATP dialog window. Now the issue is that delivery time is not copied to the new SLs. And it will be cumbersome to enter it by going into the SL-Sales tab for multiple items via their confirmed SLs. Is there a config way ( I doubt it) to get the delivery time (only time) copied to the confirmed SLs from the first SL. Or user exit is the only route? if so is it FORM USEREXIT_MOVE_FIELD_TO_VBEP in MV45AFZZ? Does this info stay once it comes via this user exit or do we need to do anything extra during Sales document save or prepare? Oh, by the way, we are set up for complete delivery and fixed date/qty checked.

Let me know ASAP. Thanks.