In cases where the carrier tenders a lump sum payment to claimant based upon medical disability, the carrier shall accompany the payment with the A-2 and a transmittal letter which shall read as follows:(1) Enclosed is our payment of compensation $_____ for injuries received on __________. This payment is based on the medical reports contained in our file. Your case remains open before the Industrial Accident Board. This payment does not represent a settlement of your compensation claim. However, there are certain requirements of the law and of the Industrial Accident Board rules with which you must comply in order to protect your claim in the future. Please call our office or the board if you require additional medical treatment or become further disabled as a result of your injury.(2) The insurance carrier shall file an amended A-2 not later than 10 days after the carrier has received a rejected lump sum payment from the claimant or has itself cancelled for any reason the lump sum payment.