thereof by the assignment or death of the other or by reason of the statute of limitations if arising out of the contract or transaction set forth in the peitition as the foundation of plaintiiFs claim or connected with the subject of the action; but the two demands must be deemed compensated so far as they equal each other.”
Thus, even an outlawed claim may be used as a setoff if it (a) coexisted with the plaintiffs’ claim and (b) arises out of the “contract or transaction” on which the plaintiffs’ claim is based.
Here, plaintiffs’ claims began accruing July 1, 1958, when the new, arbitrated market value came into play, and as actions on written contracts continued as viable claims for the next five years. (K. S. A. 1975 Supp. 60-511.) Plaintiffs’ claims were thus “alive” from July, 1958, through July, 1963; Mobil’s claim was “alive” from January, 1958, through January, 1961. They thus coexisted for at least some two and one-half years, and thereby met the first requirement of 60-213 (d). See, Tobin Construction Co. v. Holtzman, 207 Kan. 525, 485 P. 2d 1276.
The second requirement of the statute — that the claim arise out of the same contract or transmission — is likewise met. Both claims appear clearly to arise out of the respective leases, i. e., the “same contract,” even though covering different time spans. Although Mobil cannot secure affirmative relief on its outlawed claim it can use it as a matter of pure defense, i. e., as a setoff against any judgment rendered against it. See, Christenson v. Akin, 183 Kan. 207, 326 P. 2d 313. The trial court therefore erred in denying the counterclaim in toto. Mobil is entitled to a setoff for its claim for over-payments, although only against that portion of the plaintiffs claims which coexisted with it (i. e., those claims of plaintiffs accruing before January 20, 1961).
V. Interest
The trial court’s allowance and disallowance of prejudgment interest came about in this way: When the arbitrators made their award in 1958 fixing the “fair, just and reasonable” rates for sales to Northern for the next five years, MobiFs predecessor filed those rates with the FPC as its proposed new tariff. The FPC, as it was authorized to do under the Natural Gas Act, suspended the effectiveness of the new rates pending its investigation of their lawfulness.
MobiFs predecessor filed a motion asking that it be permitted to collect the new, higher rates, subject to an obligation to refund to Northern any portion which might later be found by the FPC to be excessive, plus interest at *6%.*