As I never encounter this formula "96 pp", I assumed that you wanted to default at 96% scaling. What means 96 pp? Is it 96 Point Per Inch ?
It comes up from time to time. It is among the conventions for constructing abbreviations in Latin, to indicate plural you double the initial letter. See below. PPI, DPI and LPI are another breed of beast altogether, they belong in the world of picture element patterns and not in the world of pens, parchments and papers where pp is from.
The language of printing and publishing is old, for instance, the names for the main imposition methods are mediæval (folio for folding once to produce two sheets, quarto for folding to produce four sheets, octavo for folding to produce eight sheets, and duodecissimo for folding to produce twelve sheets).
/hh
Reference:
"In some languages, the convention of doubling the letters in the initialism is used to indicate plural words: for example, the Spanish EE.UU., for Estados Unidos (United States). This convention is followed for a limited number of English abbreviations, such as pp. for pages (although this is actually derived from the Latin abbreviation for paginae)."
http://en.wikipedia.org/wiki/Acronymand_initialism#Representing_plurals_andpossessives