L.D.
If he's still acting hungry give him more...you don't have to do it all at one sitting though! At his age I would start giving him some for breakfast, lunch, dinner and this will establish meal times. I started my daughter 3 x a day around 6 months but you can mix in other things besides cereal. You may first want to consider giving him larger bottles (8 oz) too and then you could stretch out time between feedings.