distribution costs：銷售費用
more than justified: 不對等，不合適，不合算
bring about 造成；帶來，引起。
Distribution costs are typically high but are more than justified by the increased sales potential that is brought about by this wide and extensive distribution.
銷售費用壹般會比較高，但是它高過了由這個擴張的銷售系統帶來的銷售額的可能的增長，就不合算了。
把這個句子分成兩部分。Distribution costs are typically high but are more than justified 銷售費用壹般會比較高，但是（現在的情況下,它是）不合算了。
by the increased sales potential that is brought about by this wide and extensive distribution. 銷售費用比較銷售額的可能的增長：by the increased sales potential . 而the increased sales potential 是由從句 that is brought about by this wide and extensive distribution 來修飾（解釋）.