US$660 corresponds to around £431.5 according to all major currency converters online including Google.
PayPal takes 3.4%, so $660 becomes $637.56, corresponding to £417.
Yet PayPal gives me £399.5, so they took extra £18 (extra 0.04%).
Should I conclude that they don't take 3.4% as advertised, but really 3.8%? Are they just lying to everybody's face?