The control composition clause is often employed by record labels to insure that when they sign artists that write their own songs, that the labels also can license the publishing for records it plans to issue. But its also has been used to reduce songwriting royalty payments, allowing labels to pay such artists/songwriters only 75% of the statutory mechanical rate, currently 9.1 cents per song; and to limit royalty payments to 10 songs, even if an album has 14 songs.
Source: BMG Eliminates ‘Unacceptable’ Royalty Deduction, Other Labels Urged to Follow