If the HHS declared the poverty level was anywhere near $150,000 is would be a completely obvious fraud.
Again, that is irrelevant, since there is no mechanism to prevent them from doing so.
Not true, such officers and government are subject to both civil action from private citizens harmed and criminal penalty for submitting false documents and reports:
To mention two statutes which touch upon the subject of malfeasance and fraud of officials:
Title 28 United States Code Sec. 1346. - United States as defendant (b)(1)
Subject to the provisions of chapter 171 of this title, the district courts, together with the United States District Court for the District of the Canal Zone and the District Court of the Virgin Islands, shall have exclusive jurisdiction of civil actions on claims against the United States, for money damages, accruing on and after January 1, 1945, for injury or loss of property, or personal injury or death caused by the negligent or wrongful act or omission of any employee of the Government while acting within the scope of his office or employment, under circumstances where the United States, if a private person, would be liable to the claimant in accordance with the law of the place where the act or omission occurred.
Title 18 United States Code Section 2073
False entries and reports of moneys or securities
Whoever, being an officer, clerk, agent, or other employee of the United States or any of its agencies, charged with the duty of keeping accounts or records of any kind, with intent to deceive, mislead, injure, or defraud, makes in any such account or record any false or fictitious entry or record of any matter relating to or connected with his duties; or Whoever, being an officer, clerk, agent, or other employee of the United States or any of its agencies, charged with the duty of receiving, holding, or paying over moneys or securities to, for, or on behalf of the United States, or of receiving or holding in trust for any person any moneys or securities, with like intent, makes a false report of such moneys or securities - Shall be fined under this title or imprisoned not more than ten years, or both.