For the past 3 nights I have been giving my ds ...

For the past 3 nights I have been giving my ds who is 5 months old a bottle at 6pm instead of the breast and he has been sleeping really well. Last fed at 10pm lastnight then he did'nt wake again until 5.30am. This is wonderful for him he usually wakes every 3 hours for a feed day and night. Is there anything wrong with always making that 6pm feed a bottle instead of the breast (It is formula not ebm.