Stačí uložiť do súboru s príponou .vbs a spustiť v adresári s .xls súbormi, ktoré chceš upraviť:

Set aShell = CreateObject("WScript.Shell")
Set aApplication = CreateObject("Excel.Application")
Set aFso = CreateObject("Scripting.FileSystemObject")
Const xlDown = -4121

For Each aFile in aFso.GetFolder(aShell.CurrentDirectory).Files
	If Right(LCase(aFile.Name), 4) = ".xls" Then
		Set aWorkbook = aApplication.Workbooks.Open(aFile.Path)
		Set aWorksheet = aWorkbook.Worksheets(1)
		Set aFirstCell = aWorksheet.Range("A1")
		Set aLastCell = aFirstCell.End(xlDown)
		Set aColumn = aWorksheet.Range(aFirstCell, aLastCell).Offset(0, 1)
		Set aCell = aLastCell.Offset(1, 1)
		aColumn.Formula = "=A1*2"
		aCell.Formula = "=SUM(" & aColumn.Address & ")"
		aWorkbook.Close	True
	End If
Next
aApplication.Quit