Excel - VBA: Code is generating unexpected numbers (0) - excel

Question

I'm stuck on this, I don't understand why the code adds those extra zeros in column D; What am I doing wrong?
Code: https://pastebin.com/ccpqPJdz
last = Range("B" & Rows.Count).End(xlUp).Row
'Insert 3 columns on left. Add information in Row 1, add data in column D.
Columns("A:A").Select
Selection.Insert Shift:=xlToRight
Columns("A:A").Select
Selection.Insert Shift:=xlToRight
Columns("A:A").Select
Selection.Insert Shift:=xlToRight
Columns("E:E").Copy Destination:=Columns("C:C")
Columns("E:E").Select
Selection.Delete Shift:=xlToLeft
Range("D2:D2" & last).Select
Selection.SpecialCells(xlCellTypeBlanks).Select
Selection.FormulaR1C1 = "=R[-1]C[6]"
Columns("D").Copy
Columns("D").PasteSpecial xlPasteValues
Range("D1") = Time
Range("D1").NumberFormat = "h:mm:ss"
Input:
Output:

Answer 1

Avoid the Selection object. It's created as a medium of communication between the user and VBA via the screen. VBA has direct access to the Excel workbook and therefore doesn't need it. Please try this code.
Private Sub InsertThreeColumns()
Dim Rl As Long ' last used row
Dim Rng As Range
With Worksheets("NewTest") ' change to suit
Rl = .Cells(.Rows.Count, "B").End(xlUp).Row
.Columns(2).Copy
.Columns(1).Insert Shift:=xlToRight
Application.CutCopyMode = False
.Columns("A:B").Insert Shift:=xlToRight
.Columns(5).EntireColumn.Delete
On Error Resume Next
' next line will cause a crash if there are no blanks
Set Rng = .Range(.Cells(2, "D"), .Cells(Rl, "D")).SpecialCells(xlCellTypeBlanks)
If Err = 0 Then
Rng.FormulaR1C1 = "=R[-1]C[6]"
Rng.Copy
Rng.PasteSpecial xlPasteValues
End If
On Error GoTo 0
With .Cells(1, "D")
.Value = Time
.NumberFormat = "h:mm:ss"
End With
End With
End Sub
The extra zeroes that troubled you were caused by the method of defining the range where you wanted the formula to supply cell content. In your code that range is a derivative of a Selection. In the above code it's defined by starting cell and end cell. The result should be the same. It isn't because the route via the Selection object is circuitous and difficult to follow.