In the meeting 42/2008 on June 4 2008, the committee responsible for the municipalities decided to upgrade the TAO Samnak Khun Nen to a subdistrict municipality, and as the central part of the subdistrict was already covered by a municipality named Samnak Khun Nen - the former sanitary district Samnak Khun Nen - the new municipality also had to receive a new name. According to that transcript, this new name was chosen as Luang Pho Khian (เทศบาลตำบลหลวงพ่อเขียน), apparently after a famous monk from that area.
However I just started to take a look at the Gazette announcements on the constituencies for the municipal council elections - the announcement on the upgrade/rename itself wasn't published yet. But just one of the very first ones I looked into was strange, since I could not find the municipality it referred to. After some searching I noticed that in fact this municipality named Wang Bong (เทศบาลตำบลวังบงค์) must be the same as that Luang Pho Khian set up in June. However I could not find any of these transcripts changing the name to Wang Bong, I could only confirm that the new name is also used in the list of local administrative changes from the Department of Local Administration.
Seems like I have to check that list of changes in detail as well to see if there are any other changes not mentioned in the transcripts.