Suggestion on pie chart for component cost

In the latest dev blog #105 there are some ideas floating around for the pie chart and how component cost isnt hugely readable (talk starts here
My suggestion is to devide component cost into the 6 major sections in the factory (Chassis assemble, fit body, fit engine ect).
Clicking on the chart could do a drilldown, show us the top 10 components we spend the most on.
The idea being its where we can start optimizing with in-house components

Br, Porphyria