Well, seems to me the common denominator of the clauses above is that the contractor shouldn't be delinquent according to the Ts&Cs of their agreement(s) with sub(s), which should normally call for payment of subcontractor invoices within 30 days of the contractor's payment request to the government.
I glanced back at the FAR and the regs are distinct according to the contract type and form. There may also be terms in a subcontract wrt acceptance criteria of work performed, unacceptable costs, refusal of reimbursement by government, etc. which come to bear in a discussion about timing of payments. So, I'm not disagreeing with you at all, I would just say it's an area where the variables specific to the situation would need to be clarified in order to determine a Contractor's compliance with the FAR and with the subcontract.
By the letter of the law, you may very well be right--Ts&Cs timing payments to subs contingent upon timing of reimbursement by the government may not comply with FAR. For me, I'll deem what are reasonable Ts&Cs given the work to be performed, etc. The Government pays pretty fast, so if I can get terms paying me within 30 of the Government's payment, I'm satisfied, unless my customer (the sub in this discussion) needs different terms for cashflow or whatever and then I'll pitch for better terms. But generally, I'll make that pitch based on a business-need argument rather than a compliance issue. If the prime ever becomes delinquent to a point that it's causing me a problem, I may squawk to the Government. But I'm discussing stuff you may not care about... I don't know your situation giving rise to the question.
Wrt the DCAA situation, it wasn't a false claim in the sense that no work had been performed or fictitious invoices submitted. The work had been performed and an invoice submitted by the sub--the sub really didn't care to be paid until the following fiscal, so wasn't pushing the prime for payment. However, when DCAA uncovered and despite everyone's good intentions, DCAA required the payment be made to the sub or reimbursed to the government immediately--about $40k. The sub was notified to expect a check overnight delivery, they didn't complain and DCAA was satisfied.