Some escorts offer massage service, some massage attendants offer escort type service. At most reputable MPs in town, service that is informally considered "within MP limits" doesn't include BJ/FS.
For me, escort and massage services offer me totally different experiences. With an escort I want a two way interaction, where we focus attention on each other, and of course include specific intimate activities. At the MP, I'm looking for more of the session to focus on me, and my total relaxation (thats what the massage part is for). The best massage sessions IMO combine some of that two way connection, with a slow gradual sensual build to the ending. A "massage" session that is basically an escort session leaves me wanting for the relaxation part of it. Its often rushed and also not an ideal environment for the fs type stuff, and is quite limiting. There is also a concern that escort type activities may attract unwanted attention for MPs. (tho some may get off on the thrill of getting something they are not supposed to)