i am trying to book a flight in august and noticed something confusing with frontier airlines seat upgrades.
on the seat map, premium seats are shown as costing about $29 per seat per leg. however, when i select the seat and proceed to the cart, the price increases to around $77 per seat per leg.
i am not sure if this is a glitch or if there is an explanation for the price difference. has anyone experienced this before or knows why the pricing changes between selection and checkout?

