I was a little bit wrong. 5.5 is for an account in eur base currency, 7$ is for usd. BUT you can get the 1.5$/lot from paybackfx dot com or other similar website that you can choose as your IB. In fact you can become an IB to IC if you have 5 ...
by default with IC you pay 5.5$ / lot commission without having the account linked to an IB, then you create an account with a rebate website like paybackfx and there there is a procedure to say to the broker who's your IB, in this case paybackfx .. ...