I have rarely fould any massage places that offer exchange to offer anything beyond that. I have sometimes had the girl allow DATY while doing the "exchange" massage, but it's rare, that usually requires another level of upsell...
 Sometimes it has occured that the "first" appointment needs to go well with an exchange massage where you can prove to the lady that your not LE by exibiting some behavior that's "non-becoming" to LE, but that's rare and kind of old-school anyway...  
 I would advise that if you are being offered "exchange", it is just one of many ways for the girl to part you from your cash a little at a time and that your probably going to finish the appointment by her giving you a hand-job while you lay there and blow your wad in the air,,, Just hope that she don't want $20 more to clean you up when your finished - lol!