OK, I am not getting the results so I will post some data.

The end result should look similar to:
fvendno fcompany POItem PORelsDate........TotStdCost
001275 B&R Industried.............................. 1.00
001275 B&R Industried.............................. 1.00 (total Row)
002119 Roberson Tool................................ 2.00
002119 Roberson Tool................................ 3.00
002119 Roberson Tool................................ 5.00 (total Row)
002302 Unique Automation.......................... 4.00 ( and so on).

--===== If the test table already exists, drop it
  IF OBJECT_ID('TempDB..#mytable','U') IS NOT NULL
   DROP TABLE #mytable

--===== Create the test table with
Create table #mytable(
    fvendno char(6),
    fcompany char(50),
    POItemKey char(12),
    PORelsdate datetime,
    totstdcost numeric(15,4),
    ID INT IDENTITY(1,1) PRIMARY KEY CLUSTERED)

--===== All Inserts into the IDENTITY column
    Set Identity_Insert #mytable ON
--===== Insert the test data into the test table
    Insert into #mytable (fvendno, fcompany, POitemKey, PORelsDate, totstdcost, ID)
    Select '000027', 'Albany Steel', '123456 1', Cast('01/01/2018' as datetime), 1.00, 1 Union all
    Select '000027', 'Albany Steel', '123459 1', Cast('01/01/2018' as datetime), 2.00, 2 Union all
    Select '000060', 'Apple Rubber', '123455 1', Cast('01/01/2018' as datetime), 3.00, 3 Union all
    Select '000060', 'Apple Rubber', '123467 1', Cast('01/01/2018' as datetime), 4.00, 4 Union all
    Select '000080', 'Century Spring', '189456 1', Cast('01/01/2018' as datetime), 5.00, 5 Union all
    Select '000127', 'Everett Manufacturing', '223456 1', Cast('01/01/2018' as datetime), 6.00, 6

--===== Set the identity insert back to normal
    Set Identity_Insert #mytable OFF

    Select * from #mytable