You can use clock clicks -milleseconds (
Click here) for deltas:
clock clicks ?-milliseconds?
Return a high-resolution time value as a system-dependent integer value. The unit of the value is system-dependent but should be the highest resolution clock available on the system such as a CPU cycle counter. If -milliseconds is specified, then the value is guaranteed to be of millisecond granularity. This value should only be used for the relative measurement of elapsed time.
Can you post an example of what you're trying and ltm logs showing the problem?
Aaron