Matrix column based on other matrix columns

Here is one way. 

1) create a new table as the layout for the matrix columns. In my example, I've used the following code  in the new table option under modeling:

Matrix columns =
DISTINCT ( UNION ( VALUES ( 'Table'[Year] ), { "Diff" } ) )

I've added an index column for sorting purposes

 2) Create a relationship one-to-many between the 2 tables via the "Year" fields

 

3) Using simple base measures for the sum of income and cost, create the following tto use in the visual:

Icome (visual) =
VAR MXYear =
    CALCULATE (
        MAX ( 'Matrix columns'[Index] ),
        ALLSELECTED ( 'Matrix columns'[Year] )
    )
VAR MNYear =
    CALCULATE (
        MIN ( 'Matrix columns'[Index] ),
        ALLSELECTED ( 'Matrix columns'[Year] )
    )
VAR MXValue =
    CALCULATE (
        [Sum Icome],
        FILTER ( ALL ( 'Matrix columns' ), 'Matrix columns'[Index] = MXYear )
    )
VAR MNValue =
    CALCULATE (
        [Sum Icome],
        FILTER ( ALL ( 'Matrix columns' ), 'Matrix columns'[Index] = MNYear )
    )
RETURN
    IF (
        SELECTEDVALUE ( 'Matrix columns'[Year] ) = "Diff",
        MXValue - MNValue,
        [Sum Icome]
    )

Cost (visual) =
VAR MXYear =
    CALCULATE (
        MAX ( 'Matrix columns'[Index] ),
        ALLSELECTED ( 'Matrix columns'[Year] )
    )
VAR MNYear =
    CALCULATE (
        MIN ( 'Matrix columns'[Index] ),
        ALLSELECTED ( 'Matrix columns'[Year] )
    )
VAR MXValue =
    CALCULATE (
        [Sum Cost],
        FILTER ( ALL ( 'Matrix columns' ), 'Matrix columns'[Index] = MXYear )
    )
VAR MNValue =
    CALCULATE (
        [Sum Cost],
        FILTER ( ALL ( 'Matrix columns' ), 'Matrix columns'[Index] = MNYear )
    )
RETURN
    IF (
        SELECTEDVALUE ( 'Matrix columns'[Year] ) = "Diff",
        MXValue - MNValue,
        [Sum Cost]
    )

4) create the matrix using the measures on rows and the Year field from the Matrix layout table to get:

 

I've attached the sample PBIX file for you