I did a little research and these two ingredients look fairly similar. VP/VA Copolymer = Polyvinylpyrrolidone/Vinyl Acetate (VP/VA) Copolymer. PVP = Povidone or Polyvinylpyrrolidone. According to cosmeticsinfo.org they perform similar functions, both of them acting to suspend an insoluble solid in a liquid product, and help hair holds its style by inhibit its ability to absorb moisture. However, only VP/VA Coplymer's page mentions that it "dries to form a thin coating on the skin, hair or nails". I'm guessing that gels with VP/VA Copolymer would form a "better" gel cast than gels without it, but I don't have any solid evidence to turn that from a guess to a fact. IAGirl might have more or better info.

In the meantime, EWG's (Skin Deep Cosmetics Database) page here has a long list of products with VP/VA Copolymer if you'd like to have a look.
CG since 11/2011
2c /3a F /Mii, low porosity

Fall Products /Routine:
Clarifying: Herbal Essences Tealightfully Clean
Low Poo: Renpure Luxurious Argan Oil
CO: Suave Naturals Tropical Coconut or Daily Clarifying, V05 Strawberry or Kiwi Lime
Tresemme Perfectly (un)Done, Cure Care, V05 Kiwi Lime Squeeze, V05 Strawberry, Renpure Brazilian Keratin (old formula),
PT: IAGirl's as needed