I think the leveling of scripted is more than just triggered.
In some games, including V1.0, when the big bad boss reaches certain % of HP, they move onto a different set of attack patterns.

Here, what we are saying is, in addition to this, every move they will do next can be anticipated. She will jump there, she will jump there, she will do this attack next, she will call those people, she will move back 10 feet, she will move right 10 feet, an eye in the storm will appear 10 feet to the right in 5 seconds. 10 seconds later two sisters will appear.

It is extremely scripted, and Garuda is a good example. After having done it so often I am sure 8 people could write a tool and just auto-run Garuda all the time with a pre-programmed set of actions without even having to see what Garuda does.