… account for the higher walls.

Per Ben Shpigel “The left-field foul pole stands a relatively enticing 335 feet from home plate, but the distance to left-center jumps to 379 with a 15-foot wall. A 16-foot wall guards a sliver of straightaway center, which is 408 feet away, and right-center field measures 383 feet before angling in to 330 down the right-field line. The deepest part of the park, a nook in right-center, is 414 feet from home.” SOURCE: (http://www.nytimes.com/2009/02/07/sports/baseball/07field.html)