I suspect your customer use cases would have begun in Week 2. Most depositors would be able to cover payroll with the first fraction returned in the early days. Then it's a question of managing cash flow within the tranches doled out by the FDIC as wind-down proceeded. That's when the companies that had cash needs in excess of the wind-down would emerge.

At which point I think you'd find that you could no longer buy at 90%. That number applies to the WHOLE deposit balance; but after the FDIC has paid out the initial (say) 30% to 50%, the deposit to asset ratio shrinks considerably. You might loan at that rate, but then you're ultimately secured by the depositor's corporate credit.