No. WUD or write-u/down changes are not applied to written-off time entries. If a write-off occurs during billing, historical entries are reversed, and new financial details are posted through the invoice, without altering past data in closed accounting periods.
Note: The Write-Off option for time and expense entries is only available when Revenue Recognition is enabled in Settings. If Revenue Recognition is disabled, the write-off flag is hidden. Check CORE Help Center for details.