I suppose the shorter turn-around time includes the time to change out a "burned-out"
battery and its' armoured vault?
I know, the certification is exhaustive and orchestrated by the best and brightest...... And a li-ion thermal runaway is highly unlikely, because the internal short process is so not understood or expected, besides, they are now safely locked up, sort of like an X-Man Magneto character vault/cage.
So, I suppose the logic is....
We don't know how,when or why the occasional self immolation, but they are better because well, they just are, trust us.
*Plus we are running a special on some litely used 737 rudder PAC thingamabobs that check a okay, and last long time.