Field help (PRIDIVW) 

Price divider used to define whether the price is expressed for a dozen products or a hundred etc.

This field can only be entered if the unit is used to calculate the gross price. The price calculation is then based on an "n" quantity of equal units.
The "Price factor" value corresponds to the unit quantity (according to the price list setup, if in the tab Price, the "Price processing" field has for value "Value for n").