Change shows the fluctuation of the exchange balance. The change value shows you every single asset movement ( from the rate cost of the coins in it to any deposits or withdrawals) and use them for calculation.
If you would like to see the profit for copy trading, you need to open the subscription page and check the Profit Chart. Since it's calculated in the same way as the strategy profit with the TWR formula, you can compare it with the strategy results.
If you are curious to know what is TWR and how the profit is calculated, open this article.
If you see the difference in the profit results (yours and the strategy's), check out this article.