Interestingly while searching through old newspaper archives just now, I found two earlier references which mention Titanic being ready for use later in the year. One from June 11, 1911 and May 31, 1911 (Titanic's launching date). I will be submitting these articles to ET shortly.
Thanks Jason, those will be interesting to see.
There are quite a number of these references and I remember Gunter Babler documented many of them as well. It's also worthwhile noting that J. Bruce Ismay was quoted in July 1909 as saying both ships would be ready in 1911.