Problem changing R1C1 code to refer to specific, asbolute range

Hi guys, I hope someone can help me here.

I have a spreadsheet which has, in column B, a whole host of Temperature readings. What I'm doing is tracking the change in Temperature (dT) from one row to the next and, in column O, I want to put 0 if dT < 5 and 1 if dT >5 e.g. O4 = IF((B4-B3)>5,1,0).

This is in a macro because the number of rows will vary from time to time. I already have a pretty decent code to do this which is here:

'   Find dT > 5
        For i = 4 To lrow
        .Range("O" & i).FormulaR1C1 = "=IF((RC[-13]-R[-1]C[-13])>5,1,0)"
        Next i

(Contained within a With statement in a larger code).

The problem I have is that my boss wants others to be able to follow my (not complex) code and doesn't want the relative R1C1 format, preferring that I use absolute references instead. I've gotten used to R1C1 since I started playing around with code (not long ago) so I'm a little stuck. The code I thought would work is this:

'   Find dT >5
        For i = 4 To lrow
        h = i - 1
        dT = .Range("B" & i).Value - .Range("B" & h).Value
            If dT >= 5 Then .Range("O" & i).Value = 1 _
                Else .Range("O" & i).Value = 0
        Next i

The code runs without errors but doesn't apply correctly. The cells which are given a value of 1 seem quite arbitrary. Is there something I'm doing wrong?

Cheers,
Michael