I think their intent is the "S" alone stands for the word Shrek, then they have "the Musical". They want to make sure that you know the "S" means Shrek, so they put in smaller font below the "S" logo.
Broadway Shows I've Seen: Hairspray, Chicago, Little Shop of Horrors (2003), The Wedding Singer, Spamalot, Riverdance, Rent, Beauty and the Beast, Spring Awakening, Wicked, Legally Blonde, Phantom of the Opera, Sweet Charity (revival), Drowsy Chaperone, The Lion King, Dreamgirls(2010 Tour).