UDF＃值！换纸时

Question

我有一个UDF，如果开始日期小于或等于现金流中列标题的日期，则该UDF将从工作簿的另一张表中提取行项目费用并输入费用。计算时代码可以正常工作，但是一旦移到另一张纸上，我就会得到#Value！

我已经尝试过Application.Volatile，但不能解决问题。

Function Expense(Item, Month, Cost_Code)

    Dim COST As Variant
    Dim START As Date
    Dim RNG As Range

    With Worksheets("Unit Costs").Range("C1:C100")
        Set RNG = .Find(what:=Item.Value, _
                    LookIn:=xlValues, LookAt:=xlPart, SearchOrder:=xlByRows, _
                    searchdirection:=xlNext)

        If Not RNG Is Nothing Then
            If RNG.Offset(0, Cost_Code + 5).Value = "TBD" Then
                Expense = "TBD"
                End
            Else:
                COST = RNG.Offset(0, Cost_Code + 5).Value
                START = RNG.Offset(0, 1).Value
            End If
        Else:
            Expense = "Unk Exp"
        End If
    End With

    If START >= Month Then
        Expense = 0
    Else: Expense = COST
    End If

End Function