Many ebf babies cannot go 4 hours between feeds. Mine couldn't at that time & I nursed twice in every A time. You could always offer to nurse either 30 minutes after the last feed, as the fat content is high at this point, or as a small top up before the nap. You could then replace the second feed with solids, once they enter the picture. Are you sure that he waking up due to hunger, though? It might be that your routine needs a tweak again and more A time is in order. I saw huge jumps in DD's A at 5-6 months.