Yes you can go a little longer if you wish. The idea is managing the activity of the starter. You want the starter to be “active” when you use it. By 12 hours it can be pretty spent. But you can try a few things to mitigate this. You can use a little less starter to account for a longer time line, say cut it back by 20% to get you an additional couple of hours – say to 14.
Or if you’re early to rise, like me, the same day may be your preferred. Give the reduced, longer time a try. Tell me about your experience.