That’s what a contract is. In promise to pay and you promise to deliver. Would the corporations only accept $650M each if it ended up costing them $100M less to make each one? No, of course not, they’d bill the full $750M because that’s what they bid. Finding out that you underbid or under negotiated is a risk of contractual business.
Corps need to put their big girl panties on and deliver. Maybe pay the executives less next year instead.