The original Bloomberg article doesn't state: https://archive.is/tpuut
Some research (okay, okay, I used Claude) indicates that "In summary, while Congress provides the statutory authority and mandates certain specific fees, the specific amounts for most H1B fees are set through the regulatory process by DHS/USCIS based on cost recovery principles and activity-based costing analysis."
Further, "The core authority comes from the Immigration and Nationality Act (INA) section 286(m), 8 U.S.C. 1356(m), which authorizes the Secretary of Homeland Security to set fees for adjudication services "at a level that will ensure recovery of the full costs of providing all such services".
From the legislation ( https://www.govinfo.gov/content/pkg/USCODE-2024-title8/pdf/U... ):
That fees for providing adjudication and naturalization services may be set at a level that will ensure recovery of the full costs of providing all such services, includ- ing the costs of similar services provided with- out charge to asylum applicants or other immi- grants. Such fees may also be set at a level that will recover any additional costs associated with the administration of the fees collected.