There seems to be an issue for the Firework Rockets pertaining to MC:CE PS4. When making a Rocket without a star, it's Flight Duration is defaulted to 1, no matter the amount of gunpowder you put. this means that when making a starless rocket with three pieces of gunpowder to power the rocket itself. it will seem like you only put one piece instead of three. In Creative and in Survival it seems to not change. This means if you wanted to use the Elytra with a Firework without a star in it, you get a short boost. But when your firework Does have a Firework Star in it. It recognizes how many pieces of gunpowder you put into the bench for the flight duration. So say that you made a firework Rocket with a star with Flight duration of 3, you will notice that the rocket will have the longer boost that you wanted but the star will hurt you. But when you made a firework rocket without a star so you would not get hurt even though it has the flight duration of 3. it acts like it is flight duration 1. It seems confusing but you have to try for yourself to test this to know what I mean.