Identify a date as Thursday and sum the last 6 days - excel-formula

Question

I have a table with several operation codes and its hours, and I need to sum every Thursday the hours spent on each code.
Despite being able to figure it out an IF formula would do the job I got stuck with the sum of the ranges, I could get it working via VBA but I can´t apply that same solution on Formula:
WorksheetFunction.Sum(Range("E" & cCell.Row & ":E" & cCell.Row - 6))
Dim Counter As Integer
Dim cCell As Range
Dim intToday As Integer
Dim CountDate As Integer
Dim strWsName As String
strWsName = ActiveSheet.Name
Dim xWs As Worksheet
Set xWs = Worksheets(strWsName)
'Clause 101
For Counter = 4 To 34
Set cCell = xWs.Cells(Counter, 4)
If WorksheetFunction.WeekDay(cCell.Value) = 5 Then
If cCell.Row = 4 Then
xWs.Range("Q" & cCell.Row) = WorksheetFunction.Sum(Range("E" & cCell.Row & ":E" & cCell.Row))
Else
If cCell.Row >= 34 Then
xWs.Range("Q" & cCell.Row) = WorksheetFunction.Sum(Range("E" & cCell.Row & ":E" & cCell.Row))
Else
If cCell.Row - 6 <= 0 Then
xWs.Range("Q" & cCell.Row) = WorksheetFunction.Sum(Range("E" & cCell.Row & ":E4"))
Else
xWs.Range("Q" & cCell.Row) = WorksheetFunction.Sum(Range("E" & cCell.Row & ":E" & cCell.Row - 6))
End If
End If
End If
End If
Next Counter
End Sub
I would like to know how I could transform that piece of code to a formula on Excel.

Answer 1

After doing a research on formulas and variables ranges I have managed to set this formula and it is working like a charm:
=IF(WEEKDAY($D9)=5;IF(ROW(E9)<=6;SUM(OFFSET(E9;;;-ROW()));SUM(OFFSET(E9;;;-7)));"")
NOTE: My locale settings uses ";" instead of "," on formulas, so bear in mind you must change it to your locale settings.
Explanation:
The "=IF(WEEKDAY($D9)=5" formula will assess if the date is a Thursday, if it is not it will exhbit "" on the column;
The IF(ROW(E9)<=6 clause will serve to identify the limits to the top of my spreadsheet, depding on its value it will SUM diferent ranges:
If the date´s row is smaller than 6 it will run this:
SUM(OFFSET(E9;;;-ROW())). The offset will be the same as the row where the
date is.
Now if the row is bigger than 6 then I will be able to set a fixed
offset of 7 rows: SUM(OFFSET(E9;;;-7))
If one needs to change the calculation to Wednesday all you have to do is to change the number "5" on "=IF(WEEKDAY($D9)=5" numbers of the weekdays intended, here is the list:
1 to Sundays
2 to Mondays
3 to Tuesdays
4 to Wednesdays
5 to Thursdays
6 to Fridays
7 to Saturdays
Thanks to articles found on Excel Jet and Extend Office I managed to build this solution!
I hope more people can use this solution!

Answer 2

The best way to solve this was by creating a UDF, I had the help from WideBoyDixon at ExcelForum:
Public Function SumWeek(sumRange As Range, dateRange As Range, endDate)
Application.Volatile
Dim prevSheetName As String
Dim prevSheet As Worksheet
SumWeek = Application.WorksheetFunction.SumIfs(sumRange, dateRange, "<=" & CStr(CLng(endDate)), dateRange, ">" & CStr(CLng(endDate - 7)))
prevSheetName = Mid("DecJanFebMarAprMayJunJulAugSepOctNov", Month(endDate) * 3 - 2, 3) & CStr(Year(endDate) - IIf(Month(endDate) = 1, 1, 0))
On Error Resume Next
Set prevSheet = Worksheets(prevSheetName)
If Not (prevSheet Is Nothing) Then
SumWeek = SumWeek + Application.WorksheetFunction.SumIfs(prevSheet.Range(sumRange.Address), prevSheet.Range(dateRange.Address), "<=" & CStr(CLng(endDate)), prevSheet.Range(dateRange.Address), ">" & CStr(CLng(endDate - 7)))
End If
End Function