Where a statute commits to the government's disbursal of funds from a single program according to a certain formula, subsequent budgetary riders need not place a categorical ban on payment from other sources when limiting the payouts from that program in order to function as a sufficiently clear implied repeal of the initial commitment.
Absent the trappings of a contractual agreement or some sign of intent to enter into a contract, government legislation and subsequent agency rulemaking and conduct does not indicate an intention to enter into a binding contract.
Dissent: Insufficiently clear statement of repeal, explicit attempts at repeal did not pass, insurers had completed their part of the deal, judgment fund is available, contract existed.
http://www.cafc.uscourts.gov/sites/default/files/opinions-orders/17-1994.Opinion.6-14-2018.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.