For i = LBound(Schedule, 1) To UBound(Schedule, 1)
    If (Schedule(i, 1) < ReferenceDate) Then
        PrevCouponIndex = i
        Goto NextIteration
    End If
    DF = Application.Run("SomeFunction"....)
    PV = PV + (DF * Coupon / CouponFrequency)
    '....'
    'a whole bunch of other code you are not showing us'
    '....'
    NextIteration:
Next