The full-service product is new this year and the volunteers in this forum have not necessarily been informed of all the changes. In previous years, the CPA in the live assist product was not supposed to sign your return as a preparer. In some cases, the assistance was so significant that the live assistant was required to take responsibility, although this was not how the service was originally intended. I suspect that is why the full service product was created. I suspect that if you enroll in the live assist product and the assistance required is so significant that the preparer must take over, you will be required to upgrade to full service. You always sign your own return as well, regardless of whether you use any kind of paid preparer. (When you e-file, the signature is electronic.)
No one is required to use the live assist or the full-service version. TurboTax is designed so that most taxpayers should be able to use the product without assistance. You may prefer additional assistance but it is never required.
