question about ScsiPortStallExecution?

hi,
In ddk document,ScsiPortStallExecution is specified like this:
void ScsiPortStallExecution(IN ULONG Delay);
Delay:Specifies the delay interval in microseconds.The given value must
be less than a full millisecond.
My understanding is the maximum value of ‘Delay’ is 1000.But in ddk’s
source code.I can read code written like:
ScsiPortStallExecution(50*1000);
Why?
Thanks.

Jeff