The risk I take on has to go down the chain

Nothing you signed up-chain passes down by itself. If your subcontracts are still the old template with the company name changed, then the damages you are exposed to, the notice periods you have to meet and the design duties you accepted all stop with you, and the gap between the two contracts is yours to fund on the day something goes wrong.

Back to back is drafting work, not a phrase typed on an order. It means the up-chain obligations actually flowed down, the periods offset so a notice arriving to you leaves time to serve yours below, the scope split matching what was priced, and the whole thing signed before the subcontractor starts, because a subcontract "to follow" is barely a contract at all.