Unplanned Depreciation or Depreciation Override

We need to change Depreciation reserve, respectivly NBV for a few assets in tax book. We plan to do that in DEC-2009 by manupulation of month Depreciation. I made some tests using Unplanned Depreciation and Depreciation Override.

If using any of this functionality could affect on monthly depreciation amount in next period JAN-2010. I would like to keep it as it's calculated (as per date place in service and asset life)?

Thanks,

Svetla