Key legal question
Whether the claimant's invalidity had to be assessed under the extraordinary method rather than by a pure income comparison.
Extracted holding
For a self-employed person whose comparison incomes cannot be reliably determined, the extraordinary method with a functional assessment and economic weighting applies.
Extracted reasoning
The business results of only two years were not a reliable basis because invalidity-external factors likely influenced them; a workplace activity comparison had to be economically weighted instead.