Subtract Row value from previous column total

I would like to have a dax query for subtracting row value from previous column total

Like for example the total for GP column is 63.7 and the next column CustGP the values should by 63.7 - 2.2 = 61.5 but it is showing up 74.44. 

The dax query which I am using is

01_GP_Cust = Sumx(All('Act vs Bud'),[001_GP_CY])-('Act vs Bud'[001_GP_CY])

Ultimately we need to calculate

GM Impact = (Total GP / Total Sales) - ((Total GP-Customer GP)/(Total Sales-Customer Sales))

Thanks in advance