Section 378.5 - Investigation of claims(a) Upon receipt of a claim, whether written or otherwise, the processing carrier shall promptly initiate an investigation and establish a file, as required by § 378.6 .(b) If a carrier discovers an overcharge, duplicate payment, or overcollection which has not been the subject of a claim, it shall promptly initiate an investigation and comply with the provisions in § 378.9 .(c) In the event the carrier processing the claim requires information or documents in addition to that submitted with the claim, the carrier shall promptly notify the claimant and request the information required. This includes notifying the claimant that a written claim must be filed before the carrier becomes subject to the time limits for settling such a claim under § 378.8 .43 FR 41040, Sept. 14, 1978, as amended at 47 FR 12804, Mar. 25, 1982; 62 FR 15424, 15425, Apr. 1, 1997; 83 FR 16225 , Apr. 16, 2018