Take the screenshot above:
- sold 0.2 BTC at 794,000¥ = 158,800¥
- the cost basis is 158,004¥
- the transaction fee is 238.20¥
The gain should be 158,800¥ - 158,004¥ - 238.20¥ = 557.8¥
However the gain calculated is 158,800¥ - 158,004¥ + 238.20¥ = 1034.2¥
Really? I made a gain of 100% on the transaction fee?