Do you have randomization turned on:
The following is from the documentation
5.145 SET RANDOMIZE (Randomly Distribute Scheduled Start Times)

"Use the SET RANDOMIZE command to specify the degree to which start
times
are randomized within the startup window of each schedule for clients
using the client-polling mode.

Each schedule has an associated window during which execution can begin.
To balance network and server
load, the start times for individual clients can be scattered across
that window.  You can use this command to
specify the fraction of the window over which start times for individual
clients are to be distributed.  The
randomization occurs at the beginning of the window to allow time for
retries, if necessary, unless the client's
first contact with the server is after the start time for the event.

Set the randomization percentage to a value greater than 0 to prevent
communication errors that can result
from a large group of clients contacting the server simultaneously.  If
you do experience communication
errors, you can increase the randomization percentage so that client
contact is spread out, thus decreasing
the chance for communication overload and failure.

It is possible, especially after a client or the server has been
restarted, that a client may not poll the server until
after the beginning of the time window in which the next scheduled event
is to start.  In this case, the starting
time is randomized over the specified percentage of the remaining
duration of the start window."





Roger Nadler wrote:
>
> We are running the latest client on WIN NT 4.0 sp3 and are loading dsmc
> schedule. It seems only these NT machines never start on the scheduled
> time. They can be anywhere from one to one and a half hours late in
> starting. All my Novell, solar and AIX start within minutes of the
> schedule. Anyone seen this??