The mock-ups indicate that prices for seats should reflect the usage of a Flex Pass in the displayed price of a Seat. This might be technically challenging because it requires modeling a lot more state. MZD proposes that in the seat selection process, the Flex Pass customization only be used to un-lock the reserved seats.
However... if WooCommerce supports (has an API) to apply a coupon to the cart, then maybe we can allow the user to "Apply" the coupon before reaching the cart. This may still not enable updating the price of the seat, so there are two aspects of the feature that need verification: