Gross Margin

Hi Dear All,

I hope some body can guide me properly .I have a probelm to get figures from Gross margin in Power BI.

My Data type is somehow like this.

Branch No          Branch Name     Area         Entity       month    Year          sales          GM          GM%(GM/Sales)

  01                      A                      A               S             1            2017       3000         1000         33%

  02                      B                       A               T              1           2017       2000          1000         50%

So like in this formate I have data in excel sheet . I have data for 10 month for more then 50 Branches .So the main problem is this after importing data in Power BI I want to have gross margin calculation .When I want to have Gross margin for Araea A It give totaly wrong result In Card Diagram . Normaly It should calculate Gross margin from arae A or (branch   1+2) and divded into sales from Area A or(Branche 1+2). But actualy in card diagram it gives average from this result mean it just devided by 2 as normal.

I would like to have a proper detail if somebody can give .

Thanks in Advance