You are reading that correctly, but as someone who worked on the system over a decade ago, I bet he didn't have it setup exactly like the plane. I bet he tried to fire all the cylinders at once, a 25% failure rate in this configuration actually isn't bad. But on the actual aircraft they don't fire all of the cylinders at once, they are staged front to back because the power draw is too big to fire all the pyrotechnic devices at once.