one could argue that an hour of your time has the same value whether you spend it in person with the client or over the phone. I looked at your websites but was not able to determine how you operate; whether your clients come to you or whether you go to train them.
I was asking myself what I would do. My clients come to my studio which is in my house. So I do not have any overhead for traveling to a training location. If I were to train them over the phone, the clients would also not use any of my resources such as equipment and even towels. From that perspective it is cheaper for me. I would probably knock 10% off my training rate for such a session but not more because preparation is the same.
I am curious to read the responses of my fellow trainers.