PortSwigger Web Security: Business Logic, currency arbitrage - Possibility to pay less than the price in USD

Currency fluctuate all the time. Theses days EUR / USD key pair is around 1for1. It was even 1:0.99 when I was writing this report. Portswigger doesn't change dynamically the price and exchange rate dynamically. Vulnerability at the following link: https://portswigger.net/buy/pro When you want to...