Problem adjusting macro for different cell refernces

I apologise in advance if this is a glaringly obvious question, but I'm rather inexperienced when using macros.

I have written the following macro to automatically calculate/read a series of values into a new blank row.

Sub Data_Fix_test()
 '
 ' Data_Fix_test Macro
 ' Inserts formula/reads previous cells
 '
 '
 ActiveCell.FormulaR1C1 = "=R[-1]C"
 Range("B6").Select
 ActiveCell.FormulaR1C1 = "=R[-1]C &"" Final"""
 Range("C6").Select
 ActiveCell.FormulaR1C1 = "=SUM(R[-4]C:R[-1]C)"
 Range("C6:F6").Select
 Selection.FillRight
 Range("G6").Select
 ActiveCell.FormulaR1C1 = "=R[-1]C"
 Range("G6:I6").Select
 Selection.FillRight
 Rows("6:6").Select
 Selection.Copy
 Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
 :=False, Transpose:=False
 ActiveSheet.Paste
 Application.CutCopyMode = False
 Range("C6").Select
 End Sub

This works for the cells specified in the code but I need to repeat this process for multiple blank rows throughout the entire data-set i.e. I need to do the same thing 4 rows later, the another 4 rows later etc.

What changes can be made to the code to make this happen. Is it even possible... or do I just have to re-write the code adjusting for the new cell references for every 4 rows?

Many thanks.

P.S. also as a secondary question I have the following macro for inserting a blank row, every 4 rows throughout the entire data set

 Sub Insert4_v2()
 Dim rng As Range
 Set rng = Range("A2")
 While rng.Value <> ""
 rng.Offset(4).Resize(1).EntireRow.Insert
 Set rng = rng.Offset(5)
 Wend
 End Sub

How would I change this formula to insert a row every 4th row across a specified range of rows rather than across the entire data set?