Thanks for your reply. This slightly helps but can you please suggested if nested level are more than one (as TAT_Qtr in this case).
For Example if i need Minimum of dates first on Level1 than on Level2 than on Level3 and a condition that if that date is minimum of Quarter (as Running Total will be zero for that first entry and than next all subsequent entries will be dependent on that output entry) which will be Grouped By say Level1 than on Level2 than on Level3.
Consider data below for above scenario.
Report Filters Org_Code Part_Number
Part_Number Customer_Part Forecast_Dates VCN ACPM-5002-TR1 47100375 8-Feb-16 15-Feb-16 22-Feb-16 29-Feb-16 7-Mar-16 Current Fcst 2,254 662 402 402 603 Internal Orders 0 0 0 10,000 0 Intransit Shipment Qty 0 0 0 0 0 Projected On Hand (2,254) (2,916) (3,318) 6,280 5,677 VCN ACPM-5004-TR1 47100360 8-Feb-16 15-Feb-16 22-Feb-16 29-Feb-16 7-Mar-16