You forget that the stats were achieved vs. the whole league. We play in 20 or 24 team leagues, with pitchers able to throw 15% more innings than normal.

Whats this mean? Expect hitting stats to be down a certain pct(I'd say approx. 5-15%).

Thus a .250 .450 .340 guy may end up with
.225 .405 .306 stats.

Take a couple of your players, add up the stats from 20 leagues, divide by 20, then compare his stats with his actual, you will see the above happen most of the time.