That's ETH-USDT. That's the platform's main trading pair. The main pair usually has a spread around 2%. (But there are 'gas' fees to take into account here.)
You need to look at a minor pair like wLeo-ETH, and you need to look at both what it would cost you to buy and what you would get if you sold, and then calculate the difference.
RE: An Example How Uniswap Calculate The Price Of The Tokens and What Happens When A Swap Is Made