CFSchedule Overnight with one task (CF Enterprise 2016) ?

Just voted. 

Bad news/good news on this.

1) First, I'm afraid that won't work, BKBK. The first problem is pretty easily solved (and was perhaps just an oversight): you'd get a prompt saying that "You need to enter a valid Start Date in order to proceed." But the bigger challenge is you would then get a prompt that "the end time must be after the start time."  But I agree it would be nice if CF was able to support that. 🙂

2) So for Two Edge's need, it seems there's no choice but to setup two tasks, one for the 10:00:00 PM to  11:59:00 PM and another for 12:00:00 AM to 08:59:00 AM. Duplication has its drawbacks, but I don't think there's another option.

3) Finally, someone might have wondered if it may be possible to use the "crontime" feature on that CF Admin page (crontime for tasks was introduced in CF10). I can share what I have found here on that. Read on, if interested.

3a) While it is indeed posible to set a cron time that represents every 30 seconds, sadly its feature for setting the hours also does not work with the final/second hour being earlier than the first. I tried it.

3b) If someone reading this is aware of crontime and would say that it doesn't support controlling seconds, actually the CF scheduled task mechanism runs via the open source Quartz library, which DOES in fact have support for seconds (see docs here and here, which are for version 2.2.2, which is the closest doc version to what CF2021 runs, which is version 2.2.1).  There's also a nice online tool (free) to help build such a crontime for quartz, here: 
https://www.freeformatter.com/cron-expression-generator-quartz.html 

So first to run something every 30 seconds (every day all day), one could use this:

*/30 * * ? * * * 

And to run it from one given hour to another, that could be specified as a range in place of the 3rd *, such as to run from 10a to 10p:

*/30 * 10-22 ? * * * 

And FWIW, that freeformatter site has a nice feature to to turn a cron pattern into words, and that would show as "Every 30 seconds starting at second 00, every minute, every hour between 10am and 22pm, of every day".

3c) But again TwoEdge needed 10p-9a, and while the CF Admin accepted */30 * 22-9 ? * * *,  I confirmed that it started the task running BEFORE my 10p, so that won't work. (And that freeformatter site tool would NOT allow the 22-9, complaining "(Hours) - Unsupported value '22-9' for range. Accepted values are 0-23".)

3d) Further, I saw some resources suggesting that some tools accept two crontimes separated by a comma, but again while the CF Admin ALLOWED that, I confirmed that it ONLY honored the time for the FIRST crontime, not the second. 

The cron feature is indeed way more powerful than most realize--but it's also quite intimidating in that power. Tools like that above can really help. But again in this case it seems it would not help with the specific problem.

4) Twoedge, let us know if the two task approach works well enough for you, or I'll be interested to hear if anyone has a better idea, or if I missed something about the crontime.