Projecting batting average

In the glossary, under principles and splits, it mentions that in 2010, "line drives fell for hits 72% of the time, groundballs fell for hits 23% of the time, and flyballs went for hits 14% of the time. However, those percentages are based off BABIP, which excludes homeruns from its calculation; if you include homeruns, the flyball percentage bounces up to 21% of the time".

So I've taken all qualified hitters for 2010, and basically tried to determine a projected batting average.  The formula is essentially [(# of LD * 72%) + (# of GB * 23%) + (# of FB * 21%)] / AB

Now obviously this will not match perfectly, but it should give a pretty good indication on how a hitter should have fared during the season.  My results were not even close.  For example, Josh Hamilton hit .359, but with my formula, it comes out to .273, almost a 9% difference.  I took the average of the qualified hitters averages for the entire league, and I got .273.  I took my average of expected batting average based on the figures above, and got .253.

Is there any reason for this on why it is so far off?  I was expecting results within a couple of percentage points.

Thanks
asked Dec 31, 2012 in Strategy