The welcome email is triggered when a payment is associated with the booking. This could happen after the appointment, or when a deposit is paid over the phone. Paying a deposit over the phone is a completely different scenario from having a treatment. How can one email be for both? There is no way to make that email into a meaningful communication relevant to 2 completely different things, when you don't know which one has prompted the email. The Welcome email should only go after the 1st Treatment