Ah does not mean it has to be discharged over exactly one hour in some test. It's simply a unit just like kWh. And most batteries are not optimised for one hour discharge. There's batteries with insanely high C-rates for delivering a lot of power quickly, discharging in 10 minutes. And some with really low that can standby for years. They'll still indicate the Ah capacity the same way.
The C rate still comes from the amp hour number on the battery. I’m aware you can discharge faster or slower than that, but the capacity measured will not be the same