VBA Sumif based on column headers

[milanso]

Hi,
I have two worksheets. The first contains the production plan with dates for column headers and products for rows.

Product	7.2.2018	7.3.2018	7.4.2018	7.5.2018	7.6.2018	7.7.2018	7.8.2018	7.9.2018
a	150	200	550	0	0	0	0	0
b	50	200	400	600	0	0	0	0
c	0	0	600	500	500	400	0	0
d	0	0	0	800	1000	600	250	100

<tbody>
</tbody>

I needed to create a second worksheet based on the first one, but with shipping dates instead of production dates, based on criteria like,
if date 1 is tuesday, then it ships on friday, etc. Since we have two shipments per week, we will have several date headers repeating, like this:

Product	7.5.2018	7.5.2018	7.5.2018	7.9.2018	7.9.2018	7.9.2018	7.9.2018	7.12.2018
a	150	200	550	0	0	0	0	0
b	50	200	400	600	0	0	0	0
c	0	0	600	500	500	400	0	0
d	0	0	0	800	1000	600	250	100

<tbody>
</tbody>

Ive managed to do all this, but I need the columns summed for the same dates, and I'm stuck.
This should be the final result:

Product	7.5.2018	7.9.2018	7.12.2018
a	900	0	0
b	650	600	0
c	600	1400	0
d	0	2650	100

<tbody>
</tbody>

Here's the code:

Option Explicit

Sub Plan()
Dim d As Object
Dim i As Range, n As Range, v As Range, h As Range
Dim wbO As Workbook
Dim wsPlan As Worksheet, wsShip As Worksheet
Dim lRowP As Long, lColP As Long, lRowS As Long, lColS As Long, lRowS2 As Long, lColS2 As Long, rowNrI As Long, colNrI As Long




Set wbO = ThisWorkbook
Set wsPlan = wbO.Sheets("plan")
Set wsShip = wbO.Sheets("shipments")


With Application
        .ScreenUpdating = False
        .EnableEvents = False
End With


lRowP = wsPlan.Cells(wsPlan.Rows.Count, 1).End(xlUp).Row
lColP = wsPlan.Cells(1, wsPlan.Columns.Count).End(xlToLeft).Column

'Calculates which shipment date it is and writes over new value

For Each i In wsPlan.Range(wsPlan.Cells(1, 2), wsPlan.Cells(1, lColP))
    If Weekday(i.Value) = 1 Then
        i = DateAdd("d", 3, i.Value)
    ElseIf Weekday(i.Value) = 2 Then
        i = DateAdd("d", 2, i.Value)
    ElseIf Weekday(i.Value) = 3 Then
        i = DateAdd("d", 6, i.Value)
    ElseIf Weekday(i.Value) = 4 Then
        i = DateAdd("d", 5, i.Value)
    ElseIf Weekday(i.Value) = 5 Then
        i = DateAdd("d", 4, i.Value)
    ElseIf Weekday(i.Value) = 6 Then
        i = DateAdd("d", 5, i.Value)
    ElseIf Weekday(i.Value) = 7 Then
        i = DateAdd("d", 4, i.Value)
    End If
Next i

'Clears Shipment sheet

If wsShip.Range("A1").Value <> 0 Then
    lRowI = wsShip.Cells(wsShip.Rows.Count, 1).End(xlUp).Row
    lColI = wsShip.Cells(1, wsShip.Columns.Count).End(xlToLeft).Column
    wsShip.Range(wsShip.Cells(1, 1), wsShip.Cells(lRowI, lColI)).ClearContents
End If

'copies first column with the Products to new sheet

wsPlan.Range(wsPlan.Cells(1, 1), wsPlan.Cells(lRowP, 1)).Copy wsShip.Range("A1")

'Creates scripting dictionary from the shipping dates and pastes unique values to new sheet

Set d = CreateObject("scripting.dictionary")
For Each n In wsPlan.Range(wsPlan.Cells(1, 2), wsPlan.Cells(1, lColP))
    If Len(n.Value) > 0 Then
        If Not d.Exists(n.Value) Then d.Add n.Value, 1
    End If
Next n


wsShip.Range("B1").Resize(1, UBound(d.keys) + 1).Value = d.keys


lRowS2 = wsShip.Cells(wsShip.Rows.Count, 1).End(xlUp).Row
lColS2 = wsShip.Cells(1, wsShip.Columns.Count).End(xlToLeft).Column

'Tried with sumif but stuck

For rowNrI = 2 To lRowI2
    For Each v In wsShip.Range(wsShip.Cells(rowNrI, 2), wsShip.Cells(rowNrI, lColI2))
            v = Application.WorksheetFunction.SumIf(wsPlan.Range(wsPlan.Cells(1, 2), wsPlan.Cells(rowNrI, lColP)), d.keys, wsPlan.Range(wsPlan.Cells(rowNrI, 2), wsPlan.Cells(rowNrI, lColP)))
    Next v
Next rowNrI


With Application
        .ScreenUpdating = True
        .EnableEvents = True
End With


End Sub