The Commissioner may expand the scope of any such experiment or demonstration project to include any group of applicants for benefits under the program established under this subchapter with impairments that reasonably may be presumed to be disabling for purposes of such demonstration project, and may limit any such demonstration project to any such group of applicants, subject to the terms of such demonstration project which shall define the extent of any such presumption.
The experiments and demonstration projects developed under subsection (a) shall be of sufficient scope and shall be carried out on a wide enough scale to permit a thorough evaluation of the alternative methods under consideration while giving assurance that the results derived from the experiments and projects will obtain generally in the operation of the disability insurance program under this subchapter without committing such program to the adoption of any particular system either locally or nationally.
In the case of any experiment or demonstration project initiated under subsection (a) on or before December 30, 2021, the Commissioner may waive compliance with the benefit requirements of this subchapter and the requirements of section 1320b–19 of this title as they relate to the program established under this subchapter, and the Secretary may (upon the request of the Commissioner) waive compliance with the benefits requirements of subchapter XVIII, insofar as is necessary for a thorough evaluation of the alternative methods under consideration. No such experiment or project shall be actually placed in operation unless at least 90 days prior thereto a written report, prepared for purposes of notification and information only and containing a full and complete description thereof, including the objectives of the experiment or demonstration project, the expected annual and total costs, and the dates on which the experiment or demonstration project is expected to start and finish, has been transmitted by the Commissioner to the Committee on Ways and Means of the House of Representatives and to the Committee on Finance of the Senate. Periodic reports on the progress of such experiments and demonstration projects shall be submitted by the Commissioner to such committees. When appropriate, such reports shall include detailed recommendations for changes in administration or law, or both, to carry out the objectives stated in subsection (a).
On or before September 30 of each year, the Commissioner shall submit to the Committee on Ways and Means of the House of Representatives and to the Committee on Finance of the Senate an annual interim report on the progress of the experiments and demonstration projects carried out under this subsection  together with any related data and materials that the Commissioner may consider appropriate.
The authority to initiate projects under the preceding provisions of this section shall terminate on December 31, 2021, and the authority to carry out such projects shall terminate on December 31, 2022. Not later than 90 days after the termination of any experiment or demonstration project carried out under this section, the Commissioner shall submit to the Committee on Ways and Means of the House of Representatives and to the Committee on Finance of the Senate a final report with respect to that experiment or demonstration project.
For purposes of paragraph (2)(A) and except as provided in subparagraph (C), the amount of an individual’s impairment-related work expenses for a month is deemed to be the minimum threshold amount.
In this paragraph, the term “minimum threshold amount” means an amount, to be determined by the Commissioner, which shall not exceed the amount sufficient to demonstrate that an individual has rendered services in a month, as determined by the Commissioner under section 422(c)(4)(A) of this title. The Commissioner may test multiple minimum threshold amounts.
Notwithstanding subparagraph (A), in any case in which the amount of such an individual’s itemized impairment-related work expenses (as defined in clause (ii)) for a month is greater than the minimum threshold amount, the amount of the individual’s impairment-related work expenses for the month shall be equal to the amount of the individual’s itemized impairment-related work expenses (as so defined) for the month.
In this subparagraph, the term “itemized impairment-related work expenses” means the amount excluded under section 423(d)(4)(A) of this title from an individual’s earnings for a month in determining whether an individual is able to engage in substantial gainful activity by reason of such earnings in such month, except that such amount does not include the cost to the individual of any item or service for which the individual does not provide to the Commissioner a satisfactory itemized accounting.
Notwithstanding the other provisions of this paragraph, for purposes of paragraph (2)(A), the amount of an individual’s impairment-related work expenses for a month shall not exceed the amount of earnings derived from services, prescribed by the Commissioner under regulations issued pursuant to section 423(d)(4)(A) of this title, sufficient to demonstrate an individual’s ability to engage in substantial gainful activity.