I ran into an issue as the Royal Canin Puppy food the breeder was feeding in the UK is completely different than the Royal Canin Puppy food sold here in the US. I unknowingly did a cold switch of food on a 10 week old puppy. I was having poop issues and was talking to the manager of my local pet store who told me RC had changed all their formulas. I finally got Bruce switched onto Fromm Large Breed Puppy and he's done really well on it.
In general Labs are pigs and will eat as much as you feed them, they always look hungry, so it's not very hard to over feed them!!! Like I said before, with Bruce, just and extra 1/4 cups, and his poo would be very runny. When I was dealing with the initial food problem, I actually had to put him back on 4 meals a day for a couple weeks to get things right.
BTW - That pic in your post is adorable!!!
I think feeding and food are like most things with dogs. Each one is different, and it's up to us to figure out what works best. Like Jen said, you can probably just eliminate the midday meal and should be fine.