Need SUMIF to calculate a change in cost

[bluerog]

I tried to explain on the attached worksheet what I'm trying to do.

Basically, I want to take a list of sub-components and raw materials and add them up. But I need the subcomponents to change as material changes and roll into a new cost.

I think it's a SUMIF problem (which I don't know how to use). I tried and failed.

See what you can do.

Thank you much,

Roger!