19 CFR 174.28: Consideration of additional arguments.

In determining whether to allow or deny a protest filed within the time allowed, a reviewing officer may consider alternative claims and additional grounds or arguments submitted in writing by the protesting party with respect to any decision which is the subject of a valid protest at any time prior to disposition of the protest. In any case in which alternative claims or additional grounds or arguments are submitted orally, they shall be considered in the allowance or denial of the protest only if submitted in writing in conjunction with, or no later than 60 days after, such oral submission.