VBA (Excel): Filling in the gaps between hundredth mileposts

Milepost_Generator.vb

' Excel VBA Macro: This takes a list of endpoints and automatically generates rows for each hundredth point between the two columns: beginning milepost and the ending milepost

Sub Main()

With Application ' Optimise so inserting rows doesnt hang
    .ScreenUpdating = False
    .Calculation = xlCalculationManual
End With

  ' Set up prompt input boxes for user to choose the columns
  Column1 = InputBox("Choose the beginning milepoint column...")
  If Column1 = "" Or DelimitedColumn1 Like "*[!A-Za-z]*" Then Exit Sub
  Column2 = InputBox("Choose the ending milepoint column...")
  If Column2 = "" Or Column2 Like "*[!A-Za-z]*" Then Exit Sub
  Column3 = InputBox("Choose an empty column to place results...")
  If Column3 = "" Or Column3 Like "*[!A-Za-z]*" Then Exit Sub
    
    lastRow = Range("A" & Rows.Count).End(xlUp).Row ' finding last row used
    
    For i = lastRow To 1 Step -1 ' iterating from last row to 1st
        difference = Round(Range(Column1 & i), 2) - Round(Range(Column2 & i), 2) ' calculating the difference
        difference = Round(difference, 2) ' round because float comparisons are inconsistent
        If difference < 0 Then ' if difference meets your criteria
            For j = difference To 0 Step 0.01 ' how many rows to insert
                j = Round(j, 2) ' round because float comparisons are inconsistent
                Rows(i).Copy ' copy the origin
                Range("A" & i + 1).Insert Shift:=xlDown ' insert the copied row
                Range(Column3 & i + 1) = Range(Column1 & i + 1) + Abs(j) ' increment milepost
                'Debug.Print j
            Next
            If IsEmpty(Range(Column3 & i).Value) Then Rows(i).EntireRow.Delete ' remove original field
            If Range(Column3 & i) = vbNullString Then Rows(i).EntireRow.Delete ' remove original field
        ElseIf difference > 0 Then ' if difference meets your criteria
            For j = 0 To difference Step 0.01 ' how many rows to insert
                j = Round(j, 2) ' round because float comparisons are inconsistent
                Rows(i).Copy ' copy the origin
                Range("A" & i + 1).Insert Shift:=xlDown ' insert the copied row
                Range(Column3 & i + 1) = Range(Column1 & i + 1) - Abs(j) ' increment milepost
                'Debug.Print j
            Next
            If IsEmpty(Range(Column3 & i).Value) Then Rows(i).EntireRow.Delete ' Check if Cell is Blank, if so delete entire row
            If Range(Column3 & i) = vbNullString Then Rows(i).EntireRow.Delete ' Check if Cell is a null string (""), if so delete entire row
        End If
    Next

With Application
    .ScreenUpdating = True
    .Calculation = xlCalculationAutomatic
    .CutCopyMode = False
End With

End Sub