Ahh I see what you're trying to do. I don't think that would work. I would suggest building this a little bit differently. There's no way to set a schedule on a device...only a call flow. That means you can't have a phone (such as 103) set with a different schedule if it's part of a ring group. You would need to create a call flow to point calls to different ring groups at different times. So for example, point your main DID to a call flow with a time of day element, and then duplicate this example that you've taken a screenshot of, and build it a second time without device 103. Then you can route to the one you want based on the time of day. Here is an example:
So basically, there is one call flow to control the time of day, then one call flow to include device 103 that I named 501, and one call flow to not include device 103 that I named 502.
If you want device 103 to not be able to receive internal calls either during these times, you'd have to create a call flow with extension 103 in it and then apply the same time of day call flow element to it.