I feel that when you achieve a score of 700 or 800 the bosses you unlock should remain open. I can go through the lab with my hero alone and kill everything in it and both bosses solo, but with destiny spots rarely do I ever get anywhere near 700. Once you unlock something it should remain unlocked in my opinion. Moving onto normal mode does nothing for me as I still need hope bringer spirits. I also already have ironheart gear on other stuff so to have hope bringer stuff not done is a bit of a pain considering my entire inventory is full of plans.