Hi Sam!
Yes, I know about the increased range. What prompted me to mention it was that Bride stated Phillips told him he (Phillips) knew about the berg and that Titanic had been 'damaged in some way' and expected they would have to return to Harland and Wolff's, Belfast. Notice he used the word 'expected' but omitted the word 'might'. Possibly Phillips was speculating but I hardly think he would infer such a thing unless he had been discussing it with someone else shortly after impact - Boxhall?
Had that been contemplated, Boxhall would have been asked by Smith the distance to the nearest suitable port in Ireland to disembark the passengers before carrying on to Belfast - probably Cork
Smith did not at that time have full knowledge of the extent of damage. He did know the damage was to the fore part of the ship. Consequently, he would be thinking that any speed he made had to be somewhat less than full speed.
He would also be aware that the weather he had so far experienced was freakish and could not be expected to last, so a weather delay had to be one of his considerations.
Additionally, he would be considering his best options as to safe haven v. repair facilities including a suitably sized dry dock. Obviously the builder's yard would be a first choice if, as first thought, the damage was minimal.