Originally Posted by
skaya
This sounds incorrect as EY charges 20%, contrary to the norm of 10% with other carrriers.
It's a fixed percentage of the applied adult fare on day of purchase of the lap child ticket plus applicable taxes/fees. Whether the percentage is 10% or 20%, the dynamic is largely the same.
The applied adult fare is more commonly the prevailing adult fare for the route on the day of lap child ticket purchase than it is the adult fare at the time of ticketing the adult fare.