Cheapoair.com Misleading advertising. Charging different taxes and fees for same flights Internet

This company, along with all others out there, (this one being the most blatant) charge what they want. They are charging me over $350 in taxes and fees for a trip from Miami to Madrid round trip, but then it only charges me $112 for the same trip and same airline, with another country added to the itinerary. How can it be so easy for their computers to figure all these charges, but no one seems to be able to explain EXACTLY how much goes to what company or country or person out of all taxes and fees? I know why. Because if they do, then people will expect to pay the same amount for each airport's fees and taxes and they just won't be able to squeeze more money out of certain transactions. Law has to be passed forcing these companies to advertise the final price with tax and fees included, AND to explain what taxes and fees are paid and the recipient of those taxes and fees.