Convert "text character" into unique values

Hi can you try this UDF

Function SumLetters(Cell As Range) As Double
    Dim Txt As String
    Dim j As Long, MySum As Long
    
    Txt = Cell.Value
    
    Application.Volatile
    For j = 1 To Len(Txt)
        If Asc(UCase(Mid(Txt, j, 1))) >= 65 And Asc(UCase(Mid(Txt, j, 1))) <= 90Then
            MySum = MySum + Asc(Mid(Txt, j, 1)) - 64
        Else
            MySum = MySum + Val(Mid(Txt, j, 1))
        End If
    Next j
    
    SumLetters = MySum
End Function

Then say in cell A1 pur ABBBA 3 and in B1 this formula

=SumLetters(A1)

Answer would be 11