Hi Mohit
You can set alert on the scorecard column. Enable alert for the column on which you want to show the arrow/icon.
You have to bind the alert values properties to the column based on value of which you will set alert. So you can create a column in excel to calculate the difference and bind the alert values to this column.
Choose based on values option - By Values and you can set the ranges you want - probably </=/> zero in your case.
Uncheck Enable auto colors
Then You can change color and shapes of the indicators.
Does this help.
Let me know if you need more information.
Runali