. "For beneficiaries who are under 18 years of age or who are incompetent, a notice issued to the parent, guardian, or other representative, under established CHAMPUS procedures, constitutes notice to the beneficiary. (B) CHAMPUS contractors and OCHAMPUSEUR shall notify a provider of an initial determination on a claim only if the provider participated in the claim. (See ??199.7 of this part.) (C) CH" . . .