Sampey, when I trade BTC/USD and I want to sell BTC high (PING) and rebuy it back low (PONG), then my win is in BTC, e.g. I sell 1BTC for 1000 and when it falls I rebuy 2BTC at 500, therefore my gain would be 1BTC.

However, the "cumulative gain" shows the result in USD instead of BTC.