The help reads this:

Range of Days Use this option to select a range of dates to make the
application available. You can also use this option to make applications
available only on certain days of the week within a given range of dates.
Date Range To define the range of days, select a start date and an end
date, then select the days (Sunday through Saturday) within the established
date range that the application will be available. By default, all days are
selected; a day is selected when the button is depressed.

Defined: A depressed button is one which is in the down position.

However, from experience, this text in inaccurate. By default, no days are
selected. If you take default values in RANGE OF DAYS, then the
application will never be installed. From expierience, if the button is
in the up position, it is not available (default). If it is depressed
(down position) then it is available. The text reads that by default, all
days are selected and in the depressed status. But by default, no days are
selected as the buttons are not defaulted to depressed.

Also, the default time value is from 00:00-00:00 (never.)

If you use an end date that is greater than some number (such as 2069) then
the software will revert your end date after you save. If you go back
into the schedule, you can see this. You app will not run in this case.

If you specify a time range, the client does not respect it. It runs
whenever it wants to.

Spread From Start Time (in Minutes) : This feature does not work. When
using it and specifying some value such as 1380, the result is the logs on
each station show they ran at the exact same time.

This is 6.5 beta 2 of ZfDS, ConsoleOne, and Zen snapins.