Look at your very first picture: the one in the upper left hand corner. You really aren't jumping or moving your body or position much. Your bootie is out of the saddle just enough to free up your horse's back. You're solidly balanced and centered over your seat. This is a really nice position, and your horse is rewarding you with a nice jump as a result. You've really just lifted yourself lightly into a 2-point position to get out of your hrose's way, and you're letting your horse do the work.
Compare to your position in the other photos. In those, your body is being thrown forward, and your balance/weight is too far forward on the horse. You are not in a solid, safe position. If your horse stumbles when you do that, you're falling onto his neck or heading over his ears. You're trying to actually jump for your horse, which is throwing you both off balance. No need to jump for your horse. Your horse has got that part
I never learned the crest-release, and I have so much muscle-memopry for the automatic release, that I don't think I could do a crest if forced to do it. I'm not a fan of the crest release, because it doesn't let you move with your horse's head position. when you have a position like you do in your first picture, you don't need a crest release to help stabilize your self. In that first picture, you could likely just let go of the reins altogether and put your arms out to the side like an airplane and still be able to maintain your position and balance. If you can get that position down, go for the automatic release. When you're jumping ahead, you need the crest release to keep your balance. If you were to attempt an automatic release in those pics, you'd fall forward onto your horse's neck.