In my very short VP "career", (I learned to play for my Vegas 2009 trips, practiced on my computer at home, had strategy cards, and only played good paytables, w/ strategy printouts for every game in "hand), I would state that the 3x or 4x would greatly enhance my results making them even more positive.
Here in S. Florida, there are no +EV games, and not many 99+% games. The only time I play VP now is when I have FSP or redeem points for play, and than only to wash the fsp into cash. I am not ahead "lifetime" on the "fsp convert to cash" plays. I usually use it on the highest denomination available where I can play for full credits, so I'm there for the short term. (4 spins at $1.00 for my $20.00 fsp, cash out and out the door.) In fact, the games at that level ($0.25-$1.00) are probably 97% or less. I don't even care, because at the most, it will be 4 plays.