Age of eggs and sponge cakes

Ok, this has me intrigued. I was told by a visitor today that she was taught to use week old eggs for sponges. I had made a sponge this morning that used very fresh eggs, 1 from this morning and the other 3 from yesterday. They made a great sponge, very high and light. So of course I questioned this tip. Most baking will say use the freshest, especially with eggs. Anything that requires the beating of egg whites is best done with very fresh eggs. Now the tip could do with the type of sponge cake recipe being used, but I am struggling to find much on it.

I did a quick google and there was a mention of Julia Child's observation of using eggs straight from the chicken, but not much else. Oh there was a scientific paper on the age of eggs, but I could not understand it to find out what it recommended.

So does anyone know? Do you have any little sponge tips handed down from your Grandma, great aunt, anyone? I will keep on hunting, I am very tempted to ring our local CWA, as I am sure some of those ladies would know.

I have NEVER heard of week old eggs, I was always told fresher the better... including day of eggs ;)