Douglas County will resend corrected change of value notices to owners of about 28,600 real estate parcels after their 2010 notices contained an error, County Administrator Craig Weinaug said Tuesday.

Appraiser Steve Miles said Monday that the notices had this year’s and last year’s values flip-flopped, but the county did not notice the error until the notices were already mailed Friday.

Weinaug said the values did not change between 2009 and 2010 for about 11,000 of the county’s parcels, so new notices won’t be sent to those owners.

He said the county sent a template with computer fields for the values to its vendor, Kansas City Automated Mail of Lenexa. The vendor eventually provided the county with sample notices that flip-flopped the values, Weinaug said.

“Those sample notices were not correct, and we did not catch it. We authorized it,” Weinaug said.

The original mailing cost $23,000, and he expected the corrections to cost around the same amount because the county wants to add something to explain the error. Weinaug said the county was trying to contact the vendor Tuesday and likely would try to negotiate splitting some of the cost with the vendor for the second mailing.

He said regardless of who was responsible for the error, the county needed to send out corrected notices.

“We don’t budget for $23,000 errors, but sometimes in a $55 million organization, unfortunately, it’s not unusual to have an error or two like that,” Weinaug said. “We do have contingencies. It will in effect be paid out of contingencies. The cost is significant, but it’s also important that people be properly notified as to what their change in value is.”

After the erroneous notices went out Friday, property owners had until March 30 to request an appeal on their values. Weinaug said that based on when the corrected notices are mailed the county will extend the deadline from that date for all property owners — whether they received a new notice or not.