Highest number of Muban ever?

While working through the older subdistrict creations, I have run across a case where the number of muban was by far higher than in all the cases I have found before. The subdistrict Tak Fa (ตากฟ้า) was created in 1961 containing just 5 muban. However just 6 years later, 4 new subdistricts were split off from Tak Fa, each containing 10 muban, and the villages 1 to 12 stayed with Tak Fa. Thus in these 6 years the number of villages increased to the tenfold (Announcement), altogether the subdistrict had 52 muban when it was split.

Amphoe.com has just a short history of the district Tak Fa.

อำเภอตากฟ้า เดิม อยู่ในเขตการปกครองของอำเภอตาคลี จังหวัดนครสวรรค์ พื้นที่เป็นป่าดงดิบ มี สัตว์ป่าชุกชุมมาก พ.ศ. 2496 ทางราชการได้ตัดถนนพหลโยธินผ่าน โดยแยกออก จากอำเภอตาคลี โดยจัดตั้งเป็นกิ่งอำเภอตากฟ้า เมื่อวันที่ 13 ตุลาคม 2513

Which translates to

District Tak Fa originally belonged to Takhli district, Nakhon Sawan province. It was an area covered with jungle and with plenty of wild animals. In 1953 the government build the Phahonyothin highway. Because of this the minor district Tak Fa was split off from Thakli on October 13 1970.

In fact this is even not fully correct, as the district did not start as a minor district, but was created as a full district directly. The district then covered the area of the original subdistrict Tak Fa plus the subdistrict Udom Thanya which was also created in 1967 out of Hua Wai, altogether 6 subdistricts. Yet it does not give the full explanation of the rapid development of the area in the 1960s, as that main road was build several years before already. There must have been some more development programs, using the track of the highway as their starting point to convert the jungle into agricultural lands.