(1) If any claim or any part of a claim is rejected, the department may, after investigation, require the claimant to file an amended statement before action is taken. If the taxpayer submits an amended claim, the claim is reasonable, and the taxpayer has furnished substantial proof, the department in its discretion may accept the amended claim.

(2) A taxpayer may, of their own initiative, file an amended claim. If the claim is reasonable and the taxpayer has furnished substantial proof, the department, in its discretion, may accept the claim.