How to 'lock' a value in when using a Table visual

In my data, I have three Departments - New, Used, and Other.  
For Other, I need 80% of its Sales Income to be added to New's Sales Income (= New Blended Income), and 20% of its Sales Income to be added to Used's Sales Income (= Used Blended Income).

I am wanting to present a 2x2 table: Blended Sales Income by Department, with only New and Used departments showing.  

All attempts to do this filter out the Other component in the New and Used rows.  How can I effectively 'lock' the Other component in so that it is not removed by other filtering?  I trust it has something to do with KEEPFILTERS, ALLEXCEPT or the like, but can't quite get it working.

Thank you for your assistance