$ionicSlideBoxDelegate.next([speed]) - speed argument has no effect


I’m using $ionicSlideBoxDelegate.next() with a custom button to advance a slider. That works fine. However, the documentation at http://ionicframework.com/docs/api/service/$ionicSlideBoxDelegate/ suggests that I can include a number for [speed] to change how long the change takes.

I tried with several large numbers, but the transition seems to always take the same amount of time. My goal is to slow down the slide animation when someone actually pressed the next button.

Am I misunderstanding the capabilities of the next() method or is there another way to achieve this task?