((a)) ** In general** In determining whether an appraisal in connection with a federally related transaction shall be performed by a State certified appraiser, an agency or instrumentality under this chapter shall consider whether transactions, either individually or collectively, are of sufficient financial or public policy importance to the United States that an individual who performs an appraisal in connection with such transactions should be a State certified appraiser, except that—

((1)) a State certified appraiser shall be required for all federally related transactions having a value of $1,000,000 or more; and

((2)) 1-to-4 unit, single family residential appraisals may be performed by State licensed appraisers unless the size and complexity requires a State certified appraiser, where a complex 1-to-4 unit single family residential appraisal means an appraisal for which the property to be appraised, the form of ownership, the property characteristics, or the market conditions are atypical.

((b)) ** Use of State credentialed trainee appraisers** In performing an appraisal under this section, a State certified appraiser may use the assistance of a State credentialed trainee appraiser or an unlicensed trainee appraiser, except that the State certified appraiser assisted by a trainee shall be liable for appraisal and valuation work.