WooCommerce Bookings – Cost not override persons prices

Hi.

Sorry for my bad english

I created a bookable product and enabled people availability with 3 different types of people (I also enabled multiply by number of people and count people as bookings)

18 to 24 --> $4 price
25 to 50 --> $6 price
51 or + --> $4 price

So far everything works, but I have to set that if the people are more than 30, the price will be $4 per person.

I enable a new Cost, 

Number of people from 30 to 999 --> cost per block $4

It does not work, when I reach 30 the system adds same costs, calculates the price of the type of person + $4... (calculates $8 per person)

How can I make the cost calculation overide with the person type?