They say it will take about 45 days to implement the ACE module and anticipate the below process:

"Though operational, legal, and technical considerations may require alterations or modifications,
CBP anticipates that the process will involve the following steps:

• The importer files a declaration in ACE that includes a list of entries on which
IEEPA duties were paid.

• ACE runs a series of validations on each entry within the declaration and
automatically re-calculates the duty owed without the IEEPA tariffs (with
applicable interest).

• CBP verifies the declaration and processes refunds as soon as practicable.

• ACE automatically finalizes (liquidates or reliquidates) the entries.

• ACE automatically aggregates the refunds with interest by importer and
liquidation date.

• CBP certifies the refunds.

• The Department of the Treasury issues IEEPA refunds electronically."