I did something like this just yesterday with a "slow-motion" JavaScript function…
var x = 0;
setInterval(function(){
x = x + 0.01;
hypeDocument.goToTimeInTimelineNamed(x, "Main Timeline");
}, 1000);
There was a very specific reason for me doing that though. I'm not sure if that code is compatible with what you're trying to do. But in general, every 1000 milliseconds, the timeline was moved slightly forward. It turned it into a slideshow basically.
There's also the "timeScale" option with Physics… Physics Mini Templates for Tumult Hype 4 - #25 by Photics
At that post, there are links to other threads where this issue was discussed previously. It's something of a limitation of Hype.