15min, etc.)</p>
<p><em>NOTE3</em>: If you specify time offset in days, weeks, months, or years,
you will end with the time offset that may vary depending on your time
reference, because all those time units have no single well defined
time interval value (1&nbsp;year contains either 365 or 366 days, 1&nbsp;month
is 28 to 31 days long, and even 1&nbsp;day may be not equal to 24 hours
twice a year, when DST-related clock adjustments take place).
To cope with this, when you use days, weeks, months, or years
a