Does stability work? Yes. Obviously.
Does it work with 100% reliability? Are bacteria immortal and invincible? No.
Does it work immediately? No. The bacteria supplied in the bottle are unlikely to be completely sufficient. You have to wait for them to multiply, and they're not effective until they're at sufficient population because their population goes up exponentially. This means that there will be some buildup of ammonia/nitrite before stability takes care of it.
The simplest solution to these problems is to do a fishless cycle with stability. It should take less than a week if stability's claims are true. Add ammonia 3ppm, add stability, wait for ammonia/nitrite to zero, add fish.