EXCEL - add formula on specific cells during the insert process

Hello everybody!

Need help on my macro. I would like insert a row based on a cell and add formula on specific cells.

I have already figured out how to add a row based on a cell -

Sub InsertRowEtc()

Dim myRow As Long
Dim myCount As Long
Dim myCol As Integer

myCol = 3
myCount = ActiveSheet.UsedRange.Rows.Count

For myRow = myCount - 1 To 1 Step -1
If Cells(myRow, myCol).Value <> Cells(myRow + 1, myCol).Value Then
Range(Cells(myRow + 1, myCol), Cells(myRow + 1, myCol)).EntireRow.Insert

End If
Next myRow

End Sub

This inserts rows based on the 3rd column (in my attachment, it's the Vegetable column. In my attachment. I have two tabs - one is what the result should be and the other is what the raw/original data looks like.. Basically I need to insert gray rows in every different Vegetable (column C).

I would like to add a formula for sumifs and averageif for column L, M and N. But my ultimate problem is I have no idea how to convert AVERAGEIF formula to a 2003 version. I have worked with COUNT then IF or even COUNTA then IF then use them for my SUM IF but to no avail.. Or even AVERAGE IF but I always have a problem with those data that skip their numbers (ie Amount, Count and Average column as seen on my attachment.)
I have 7000 rows of this to work on so a Macro would come in handy.

Any help is a great help.. Thanks guys!