Calculate each values in slicer selection

So for this you want to pick up 5 vendors and apply to those the parameters correct?

I assume you have a table for vendors (dimension and another with the fact tables and a measure that you are using to be changed. 

Create the following measure:

Total adjusted = 
VAR test =
    CALCULATE (
        COUNTROWS ( ALLSELECTED ( 'Vendors' ) ),
        FILTER (
            ALLSELECTED ( 'Vendors'[Vendor] ),
            'Vendors'[Vendor] <= MAX ( 'Vendors'[Vendor] )
        )
    )
RETURN
    SWITCH (
        test,
        1, [Total Sales]+ [Vendor1 Parameter Value],
        2, [Total Sales] + [Vendor 2 Parameter Value],
       [Total Sales]
    )

In this case I only have two but you can have 5 or more:

Check PBIX file attach.