Unfortunately changing this value to a lower value will not solve the problem of the workflows only being triggered once every 5 minutes. They will still only be triggered every 5 minutes. Even running this job manually will not trigger the workflows.
I'm still looking for a way to lower this value. I haven't found a solution yet, but will update this page when I do.
An important thing to notice is that when you set your delay in your workflow to being 5 minutes also, it might very well occur that the workflow will only be triggered once every 10 minutes since the current time + 1 second execution time for the workflow > current time + 5 minutes when the next workflow action runs. So if you want to use the lowest possible value of once every 5 minutes, be sure to set your delay to something lower than 5 minutes.