(a) The representative may at any time pay or consent in writing to all or any part of any claim that is not barred under Section 18-12, if and to the extent the claim has not been disallowed by the court and the representative determines it to be valid. Payment or consent by the representative constitutes allowance of the claim and binds the estate. When a claim filed with the court is allowed by the representative, the representative must promptly file notice of the allowance with the court, but failure to do so will not affect the allowance. At the request of any interested person the representative must establish the propriety of his allowance of any claim.
     (b) The representative may at any time disallow all or any part of any claim that has not been filed with the court by mailing or delivering a notice of disallowance to the claimant, and to the claimant’s attorney if the attorney’s name and address are known to the representative, stating that if the claim is not filed with the court on or before the date stated in the notice, which date shall be not less than 2 months from the date of the notice, the claim will be barred. A claim disallowed by the representative under this subsection and not filed with the court on or before the date stated in the notice shall be barred under Section 18-12 in the same manner as a claim not timely filed.