And nobody answered on my question : Is 10 USD fee NORMAL?
First of all, I've checked your numbers and in my case they are different. 669.96670022 and 666.62522041. On the right side I have 666.62522041 instead of 668.something, even worse than you.
Also if you enter the same number in a different order, the results are different (LOL).
Now the answer to your question, with my numbers:
0.39242276 * 1703.00000009 = 668.29596031
left side: 669.96670022 - 668.29596031 = 1.67
right side: 668.29596031 - 666.62522041 = 1.67
1.67 / 668.29596031 = 0.0024 = 0.24%
I knew of 0.20% fee, but it looks like it's closer to 0.25%.
However, the math looks pretty good imho.
Edit: I don't get your 10$ math. I've set the same numbers in the first cells at left and right to make everything correct and not compare apples with oranges. I hope that you have understood mine.