excel中的用户定义函数在VBA中工作，并在工作表中返回#value错误

Question

我设计了一个UDF来获得没有促销期的产品的平均销售额。
它应该如何工作，它将促销期间的销售价值替换为""，然后获得销售的平均值。
需要注意的是：同一产品可能有一个或多个促销期 它在VBA或MsgBox中调用时效果很好，但在工作表中返回#Value

Public Function promless(itemcode As Range, daterange As Range, salesvalues As Range) As Double

 Application.Volatile

'find promotion rows

Dim porrange1 As Range
Dim pormotionrow() As Long
ReDim pormotionrow(1 To 10)
Dim code As String
code = itemcode.Value


   Set porrange1 = Sheets("por").Range("a:a").Find(code)
  pormotionrow(1) = porrange1.Row

If Not pormotionrow(1) = 0 Then
  For n = 2 To 10
   pormotionrow(n) = Sheets("por").Range("a:a").FindNext(porrange1).Row
   If pormotionrow(n) = pormotionrow(n - 1) Then
     pormotionrow(n) = 0
     Exit For
   End If
  Next
End If
Size = n - 1
ReDim Preserve pormotionrow(1 To Size)
'-------------------------------------------------------------------------------------
'put sart and end of promotions
Dim porstart(), porend() As Variant
ReDim porstart(1 To Size)
ReDim porend(1 To Size)

For n = 1 To Size
  porstart(n) = Sheets("por").Range("c" & pormotionrow(n)).Value
Next

For n = 1 To Size
  porend(n) = Sheets("por").Range("d" & pormotionrow(n)).Value
Next
'--------------------------------------------------------------
'get data range date and apply pormotion conditions

Dim daterangearr As Variant
daterangearr = daterange.Value

For n = 1 To daterange.Columns.Count
  For i = 1 To Size
    If daterangearr(1, n) >= porstart(i) And daterangearr(1, n) <= porend(i) Then
     daterangearr(1, n) = "por"
    End If
  Next
Next

'----------------------------------------------------------------
'get sales values

Dim salesvaluesarr As Variant
salesvaluesarr = salesvalues.Value

'check if the date range is the same size of sales values
If salesvalues.Columns.Count <> daterange.Columns.Count Then
  MsgBox ("date range must be same number of sales values")
End If

'empty sales values that are in pormotion
For n = 1 To salesvalues.Columns.Count
  If daterangearr(1, n) = "por" Then salesvaluesarr(1, n) = Empty
Next
promless = Application.WorksheetFunction.Average(salesvaluesarr)

 End Function

在我获得促销信息的工作表中：

并且原始工作表包含销售数据：