Activate light more than 15 min

The app allows you to turn on lights and stay on for 1, 5, 10 and 15 min. It does not allow to extend it for more than 15 min. This feature is ideal if you want to turn on the lights at a specific brightness for longer period of time. My request is to add the 'custom' option so you can set the time. I understand that this is limited due to battery but still this should be the user decission. Thanks!