If you have a used manufactured home without land the transaction is exempt from the general HPML appraisal rules and all you are required to obtain is either:
1) a cost estimate of the value of the manufactured home securing the transaction obtained from an independent cost service provider; or
2) A valuation, as defined in § 1026.42(b)(3), of the manufactured home performed by a person who has no direct or indirect interest, financial or otherwise, in the property or transaction for which the valuation is performed and has training in valuing manufactured homes
and ensure you provide a copy of whichever you use to the consumer no later than three business days prior to consummation of the transaction.
In the supplemental final rule the CFPB states that NADA is a provider they anticipate creditors utilizing for used manufactured homes without land. See p. 78566.
https://www.gpo.gov/fdsys/pkg/FR-2013-12-26/pdf/2013-30108.pdf
The dollar threshold is a stand-alone exemption.