Power BI Desktop Row context issue

Hello,
I have table with 8 location 
i want to create a table single table visual location weir1 to weir 8 but weir 8 = weir1 -weir8 
Ex. weir 8 value shuld be=  6157.861-6381.312 =-223.751
the Weir 8 --- 6381.312 value should be replaced by 223.751 values

Please help on this problem..

awaitng a solo