Honestly I'm not sure exactly how the integration works between Roll20, D&D Beyond, and Beyond20 with regards to API scripts. I was told by the Beyond20 creator that as far as how Beyond20 works in Roll20, it simply posts chat messages... but since it automatically updates hit points, that means there is some kind of javascript functionality (because chat messages can't update token settings without the API). What I've noticed is that Aura/Tint Healthcolors can be fairly system intensive, because it is basically monitoring all the tokens for any changes to their bar values, and then adjusting their auras/tints based on a computation of the percentage out of the max value for the linked attribute, and applying special effects on top of that. What I've noticed is there is often a significant delay to those things processing, especially if there are a lot of tokens on the page. I modified the Aura/Tint Healthcolors quite a bit to remove several of the functions - I only use one aura, I changed the 'death' effect, and I think a couple other minor things that I can't remember.