Iowa Code § 633.445

At the time of the filing of an answer to a claim, the personal representative shall plead all offsets against the claim, and shall plead all counterclaims against the claimant of which the personal representative has knowledge. An offset or counterclaim may or may not diminish or defeat the recovery sought by the opposing party. It may claim relief exceeding the amount, or different in kind, from that sought in the claim.