Have to admire the poster who could remember a 6 year old thread!
Surprised there hasn't been a queue of posters asking why you need to pay for any more than 15 minutes. If there is one thing I have learnt from this forum is that no two punters are after the same thing. For some, it is about how many times they can pack into a session. For some, it is the GFE that is important, for others it is timewasting.
Only you can know what is important to you. It is worth experimenting, however. If you are used to hour sessions, for example, try a half hour session with one of your regulars ("sorry, I am pushed for time today"), and see how you get on.