EF Fare information is not always helpful. For example, some airlines load additional fees on top of the base fare. What you'll see in the EF fare data is the base fare. So, if you look at BA it's not quite clear what you're actually paying. That low base fare is bumped up by the YQ fee, thus making the EF fare data less than useful when searching for low fares. The fully loaded fare (including fare, airline imposed fees, gov't imposed fees, and taxes) will be found using the Google Flights search engine. That's where you should spend your time.