The start case number must be less than the end case
number.
The start can be any observation ranging from the
second observation in the historical period that is specified on USE to the observation immediately following
the end of the historical period. If USE is not specified, the start can be any observation ranging from
the second observation in the series to the observation immediately
following the end of the series.
For most models, the start of the predict period
should not be too close to the start of the use period.
The predict and use periods should not be exactly
the same.
The start of the predict period should not precede
the start of the use period.