Each attribute level has a cost associated to it. The overall product cost is equal to sum of the individual costs of the components (attribute levels) and a base cost for that product. There is NO random shock to the sum of the individual costs, but the base cost varies by +/- 20% (three values). Respondent is only shown the total product cost (base cost+sum of component costs).
What is the best way to solve the cost attribute given that a given configuration has always the same summed component cost, but could have a different base cost?
1) Solve the total product cost as an attribute (linear)?
2) Solve only the base cost with its three levels, as summed component cost remains constant for a given configuration?