Find previous row using index on a filtered table

Hi jefflynn 

If I understand correctly, can you achieve this with a calculated column using DAX

CostToComplete_Column =
VAR PreviousRow =
MAXX(
FILTER(Query1, Query1[Index] < EARLIER(Query1[Index])),
Query1[Index]
)

VAR PreviousEstCostAgg =
LOOKUPVALUE(Query1[EstCostAgg], Query1[Index], PreviousRow)

VAR PreviousActualCostAgg =
LOOKUPVALUE(Query1[ActualCostAgg], Query1[Index], PreviousRow)

RETURN
IF(
SEARCH("SUB LABOR", Query1[Description2], 1, 0) > 0,
PreviousEstCostAgg + Query1[EstCostAgg] - (Query1[ActualCostAgg] + PreviousActualCostAgg),
BLANK()
)

Find the seccenshot below 

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