I understand that what I am proposing would take some work, however this suggestion would be of benefit to those using the auto-play hero timing system. Instead of making players work out their teams ultimate skill timings in relation to a bosses attacks, especially when there are variables in place like energy reduction and ultimate skill resets which make it difficult and unreliable, could you add token sliders that a player can move along the bosses skill bar to specifically set when that heroes ultimate skill would be executed? (See example picture)
When the bosses energy skill bar reaches the intersection with that of the hero marker, the hero skill is executed. This is no different in terms of function to that of being able to customize the timers, but rather makes it easier to visualize exactly when these skills would be cast and instead of using time trigger, functions from the statement that "when the bosses skill energy reaches this point, execute this heroes ultimate skill. Further indication of the initial cast and subsequent cast could be set in a timer section but the player could also move the slider to where they want the cast to take place.