DAX Code not working

[Singh_Yoshi]

I have following table in BI. 

Item	Cost
18" Alloy	-23000
20" Alloy	31000
Air Bag	5000
Deatc	250

I want to subtract 18" Alloy cost(-23000) from 20" Alloy(31000) and remove 18" Alloy from the table. I Used following Dax function and it returns above table as out without doing any subtraction. Please correct my code or help me with new code. Thank you in advance.
Used DAX:

IF (
[Item] = "20"" Alloy",
[Costs] +
CALCULATE (
SUM([Costs]),
[Item] = "18" Alloy"
),
FJ11_16[Calculated Costs]
)

Desired Output:

Items	Cost
20" Alloy	8000
Air Bag	5000
Deatc	250

[Singh_Yoshi]

@danextian Thanks a lot. It is working. Please keep solving my queries.

[danextian · Accepted solution]

Hi @Singh_Yoshi 

Please try this:

Measure1 = 
VAR _alloy =
    CALCULATE (
        SUM ( SampleData[Cost] ),
        FILTER (
            ALL ( SampleData[Item], SampleData[Cost] ),
            SampleData[Item] IN { "18"" Alloy", "20"" Alloy" }
        )
    )
RETURN
    SWITCH (
        TRUE (),
        SELECTEDVALUE ( SampleData[Item] ) = "18"" Alloy", BLANK (),
        SELECTEDVALUE ( SampleData[Item] ) = "20"" Alloy", _alloy,
        SUM ( SampleData[Cost] )
    )

[Singh_Yoshi]

I have a following table called Table1,

Model Code	MSRP	LC
FJ11	1392000
FJ16	1580000	188000
FJ7	1762000	182000
FJ8	1912000	150000
FJ15	1937000	25000
FJ12	2279000	342000

I have few measures as below names and consists of Items and Cost

• FJ11-16 - Sum of the measure is (-1674)
• FJ16-7 - Sum of the measure is (70650)
• FJ7-8 - Sum of the measure is (176150)
• FJ8-15 - Sum of the measure is (-68150)
• FJ15-12 - Sum of the measure is (28500)

1. Now I want to subtract LC cost - SUM of each measure

2. I need the percentage of (LC Cost - Sum of each measure)

Kindly help me with DAX code