Work field edits causing actual work to populate

[Wendy]

Hello,

We are working in Project Server 2003 using managed time periods. In a
plan, there are many tasks set up as Fixed Work, ASAP and are showing
zeros in actual work for future weeks. When the PM goes the Work field
for these tasks, the "your action may result in data becoming out of
sync..." and in some instances, actual work actually populates. When
you sync back up, the entered work goes away.

Can anyone help with:

1. Why are the zeros showing in the Actual Work field for future
periods (not submitted by resource)?

2. Why are we getting a sync message when modifying the Work field?

3. How can we modify the Work field for this task without getting
errors?

Any assistance is appreciated.

Thanks!
Wendy