According to the method disc priest page with spheres harmony the method guide she states to get off 5 blasts
each blast is 5 stacks of boon of the ascended so 5 x5 = 25
spheres harmony leggo says takes off 3 seconds of cooldown per stack
so 5 x 3 = 75
so we can drop 75 seconds
prbolem is…the leggo says MAX 60 seconds.
so maybe she did not update it and we only need to reach 4 blasts?
i.e 4 x 5 = 20
20 x 3 = 60 seconds