Electionz chief returning officer Warwick Lampp said the mistake had been caused by a "printing and proofing error".
"The moral of the story is that these types of errors do occur. It's human error. Despite all the checks these sorts of things sometimes do happen," Mr Lampp said.
He said the error was spotted in time to correct before sending the profiles out to Masterton and Tararua residents, but was too late to fix for the 1261 people in the Masterton Licensing Trust Carterton boundary.
"Due to the printing time we couldn't fix [the packs] in Carterton so the only option was a letter to each of these residents saying the profile you have got is not the correct one, here is the correct one."
He said Mr Kershaw's response to the mistake had been "considered and realistic".
Electionz deals with 39 of the 79 councils nationwide and Mr Lampp said he was not aware of any other mistakes. "[But] there probably has been somewhere. There's (sic) quite a lot of councils we don't do."
The error did not effect Mr Simmons, whose profile ran correctly, and he was unaware of the mix-up but found it humorous, joking: "I'm going to be busy. I'm going to be all over the place."