Activity Schedule Object - hours in 0-24 range

Hello.

A cording to docs hours are in 0-24 range, inclusive, 'from' must be smaller then 'to'.

Its bit confusing:
0-0 does not work, so if 0-1 means 'first hour of the day' then 'to' is not inclusive.

0-24 does not work (25 hours if 'to' is inclusive)

0-23 works and so does 1-24 - both means 'whole day' because its 24 hours?

Then, if I set 1-23. is 23 hours (not including the first hour of the day)?

I think few examples can help because we can't have both hour 0 and hour 24 - at least not on this planet :)

Thanks
Misha