BOOKING CHARGES MORE THAN TWO GUESTS

Hello, my name is Maria and I am a new host. In my settings, I had selected every guest after the two guests to be charged extra. However, I had a booking earlier today for 4 persons (2 parents, 2 children) and there was no extra payment for the additional two guests (children).

Can you explain me why did that happen? How can we fix it?

thank you in advance,

Maria