Should I avoid a one hour sleep()?

I'm using the DigitalOcean API to create droplets when my web application needs the extra resources. Because of the way DigitalOcean charges (min. one hour increments), I'd like to keep a created server on for an hour so it's available for new tasks after the initial task is completed.

I'm thinking about formatting my script this way:

<?php
createDroplet($dropletid);
$time = time();
// run resource heavy task
sleep($time + 3599);
deleteDroplet($dropletid);

Is this the best way to achieve this?