@itonewbie  “the COVID-Related Tax Relief Act limits this to §6428(f), which only deals with the Advance Refund.”

Are you sure of that? This is what you quoted and I’m reading:

EXCEPTION FROM REDUCTION OR OFFSET .— Any refund payable by reason of section 6428A(f) of the Internal Revenue Code of 1986 (as added by this section), or any such refund payable by reason of subsection (c) of this section, . . .

Subsection ( c) of “this section” still refers to Section 6428A, which sets the AGI limits on the subsection (a) credit otherwise allowed. And yes, they intentionally omitted the offset for delinquent child support, because it created too many “injured spouse” cases.