The rice cereal may also be confusing the issue, as in the early days it doesn't actually always take the edge of hunger & babies can get upset tummies that are confused for hunger. I would try to get the milk feeding sorted, before going to solids to fill up.
Also have to agree with Deb, this is the age of distraction & sometimes they just don't feed properly in the day & so need to fill up at night. I often feed Liam, then give him a kick for 5mins & offer again, most times he takes the same size feed the second time & does good long stretches at night & he is a heffalumpa at 9kg & 72cm (20lb & 28.5inches) & only 4.5 mo... if I don't do the second offer on most of his 4 day feeds, he will wake for a 2nd night feed ( he only feeds at 3/4am, no df) & then feed 3 hourly in the day & then cycle of 3 hourly at night... so I know he gets distracted!