The Capital Academy didn't publish Crown Prince Edward result for a reason and it was mostly to maintain the image of the Royal Family. However, they would still send the real result report to the Yellow Kingdom's King.
In this way, the Yellow Kingdom's King also knew the two princes' performance in the Capital Academy.
It would have been fine if Crown Prince Edward was the only son.
But..
Looking at the second prince's result that was far better than Crown Prince Edward, the Yellow Kingdom's King felt that this kid was actually much better than his older brother.
Because of his business, the Yellow Kingdom's King had no time to spend with his children. These two children would grow up on their own and it was usually Queen Ella who was in charge of their study and the likes.
So the Yellow Kingdom's King never knew that his second son was actually more promising.