In my 1989 SG South America Part 20 I do not have a SG106. The numbers go from 103 to 108. The stamp shown is SG48 or SG49 depending on the type of overprint.
The Scott classic catalog lists a "perforated across the middle" variety for each of the 2 overprint varieties. According to the 2007 catalog:
Large "P" and wide "V" in Provisorio
42b Mint $30 Used $22.50
Small "P" and narrow "V" in Provisorio
42 Mint $4 Used $4
I am assuming the stamp was perforated across the middle to make a 1/4 centavo stamp.
I did not dig around too much on the site below but maybe the answer lies there or in one of the links:http://www.filateliaargentina.com.ar/main.eng.html