I would worry if your Mazda 6 is a diesel lol
Apart from that, if is a petrol engine you will notice more fuel usage, but the RON of E10 is RON94.5 so it is better than the low grade and almost the same as the middle grade fuel
Regular fuel is 91ron, premium is 95 and super is 98 so yeah don't worry about it. You can run it without a problem, it will run like a dog for a tank if you usually put super, then it will tune itself to retard the base timing more and more, and it will feel the same as normal, but it will use more fuel. If you usually fill premium, you won't notice a difference apart from fuel spent.