Why are rankings sometimes different than the projections?
The rankings are based on the projections, the reward and the risk factor. For example, Ryan Grant is projected to have more points than Maurice Jones-Drew but Jones-Drew is a much safer pick and I would still select him before Grant even though Grant is more likely to have better statistics.
What are risk and reward?
The risk factor is an indicator of how much lower a player could finish in the end of season rankings and the reward factor is an indicator of how much higher he could finish in the rankings. For example a low risk and low reward player could be a player who has little upside because his number of touchdowns or carries will be limited but who has been known to be consistant, pretty durable and has an offensive line with pretty good depth.