Ps successfully tried a products liability action against Chiles Power Supply Company, and D, which designed and manufactured a defective hose that was installed in Ps' and the two entities' heating systems. The jury awarded Ps approximately $ 1.3 million against D, including repair and replacement costs, diminution in value damages, and 'other costs and losses' incident to having to repair and replace their heating systems. In addition, the jury found that D was responsible for 36% of such 'other costs and losses' suffered by the Berzins and Dickes and 48% of those incurred by the Sumerels and Mr. Kaufman. The court awarded prejudgment interest on the repair costs but not on the 'other costs and losses' awarded to Ps. Both sides then appealed. The division eventually remanded the case to the district court 'to determine from the existing record the proper accrual dates for prejudgment interest on other costs and losses' and to calculate and award such interest. D's lead attorney discussed with Ps' lead attorney a potential compromise on the applicable accrual dates. Although the parties appear to have agreed on the applicable accrual dates with little difficulty, they had trouble getting their calculations of prejudgment interest based on these dates to match. After a good deal of back and forth, and after reviewing these charts, P noticed that D's calculations did not agree with Ps' numbers. D's calculations were erroneously based on a wrongful allocation of 100% of those costs and losses to D. This was in contrast to other categories of damages set forth in D's charts, in which D had correctly applied the jury's fault allocations. D's error resulted in an overstatement of the damages due by more than $ 550,000. P did not call this obvious error to D's attention or the attention of any other representative of D. P accepted D's November 2, 2006 'offer.' P then followed his voicemail with a fax confirming the acceptance of that purported 'offer.' Before anyone had signed the satisfaction of judgment, D realized the error in his earlier calculations. He immediately called the error to P's attention and sent P corrected versions of the charts and a revised satisfaction of judgment with corrected numbers. P demanded that D adhere to the parties' alleged agreement, which would have resulted in Ps' receiving over $550,000 more than what was due them. D refused to do so, Ps filed a motion to enforce the purported 'settlement agreement.' The district court granted Ps' motion, and D now appeals.