Pass those amounts sound very similar to O. Last time O was weighed (at 12 months) he was 9.7kg, so P sounds a good weight!
We get the odd days of mammoth eating too YW. However, I suspect I ration him more than he would like. He never refuses something offered! We went out this evening, leaving MIL in charge of dinner. He had roast veg (large chunks of sweet potato, parsnips and carrots) 2 potato waffles, a sausage, half a pack of sweetcorn rings, 1 and a half bananas (!!!) (he'd already had one for lunch arghh!) and a tangerine.
Now if I'd been feeding him, I'd have only offered the tangerine after his main meal. And that is it!
He's between 50th-75th centiles for weight, and doesn't seem hungry between meals. So I just stop when I think it is enough.
But then he will have days where he is whinging and I just know he is hungry.
Breakfast I know he would eat 2 weetabix, which is why I still add the puree or mashed fruit to it. He'd eat 2 crumpets too! Which seems crazy?! That is an adult portion to me?! I'm not sure what the best thing to do is!
I had a WTF moment earlier today. MIL arrived here to watch O while me and DP went to the cinema. I nearly wet myself as we were both wearing pretty much identical outfits!! Skinny jeans (I finally got a pair - that fit, and look really flattering!!) with the same tshirt from New Look, but in a different design (but still a very similar design!). We also have black belted mac type coats, and identical scarves, which we were both wearing.
Poor DP. He shacked up with a younger version of his mum!!!! 
(His mum is 47 - we have similar tastes. It was bound to happen one day!!)
PS. I got skinny jeans in New Look, which are pretty flattering - for £20! I'm very happy - I haven't been able to wear jeans for a LONG time.