Believe in service 2015, a more interesting Q is "what will they do with them?" as they have the same number of Boeings on order & a mixed similar sized fleet is seldom associated with profitability.
Suspicions that it is a "tactical order", thereby blocking others options, have been mooted,if not this, it was certainly a strange thing to do.
Compare Ryanair/Easyjet profitability with SAS, although the reasons lie deeper than that obviously