Finding Max Days per row

Hi srlabhe 

Try this:

CO with top days = 
CALCULATE (
    -- Get the CO with the highest [Days CO] in the current filter context
    MAXX (
        TOPN (
            1,
            -- Create a table of COs with their corresponding [Days CO] values
            SUMMARIZECOLUMNS ( 'Table'[CO], "@value", [Days CO] ),
            [@value], DESC  -- Sort descending by [Days CO] and take top 1
        ),
        [CO]  -- Return the CO name (could also use [@value] to return the max value)
    ),
    ALLSELECTED ()  -- Respect slicers and visuals while removing row context
)