AutoFilter FormulaR1C1 R[-1] Error

Hi,

I've got a spreadsheet where I'm trying to apply populate a formula into certain rows. In order to try and avoid lengthy loops, I'm trying to filter based on certain criteria, and just apply the formula to those rows.

So, I kept getting #REF! errors in the cells where I was populating the formula, so I've stripped it down to the very basics, and essentially, it's having trouble with the negative R[-1] in the formula. So I've got the following code:

PHP Code: 

Sub PopulateFormulae()

Dim WS As Worksheet

Set WS = Sheets("Sheet 1")

'Go through each of the years where the formula should be appplied
For i = 2010 To 2014 Step 1

WS.Range("A2").AutoFilter Field:=7, Criteria1:="=" & i

    'Add the formula
    With WS

        With .AutoFilter.Range

        .Columns(14).Cells.FormulaR1C1 = "=R[-1]C"

        End With

    End With

Next i

End Sub 


If I replace the:

PHP Code: 

"=R[-1]C" 


with

PHP Code: 

"=R[1]C" 


it all works fine, but the -1 keeps bringing up #REF! errors.

I thought it might be because the row above is not in the filtered range, but then neither is the row after (ie the R[1] row)

I have noticed that it is also adding the formula into row 1 (ie my header row) and wondered if this might be related. However, I don't understand why that would bring up an error in every row.

Does anyone have any ideas where I'm going wrong?

Thanks!