Of course they wouldn't advertise something like that, they just say it privately.
Some escorts might prefer a client with a small dick who cums fast instead of someone who does "side" sex for the whole hour.
Different strokes for different folks.
Back to subject: I would only recommend an escort to give a discount to most doable clients (HWP, younger, clean, easygoing) after a first meeting! Some potential clients misrepresent themselves when it comes to age, body type, etc.