Namlakhorn with STPC QR provide the visa and transport to/from the hotel.

I do not know the exact procedure but my understanding is that you sit in the lounge enoying refreshments whilst a staff member deals with immigration. This is basically what Al Maha arrivals service does.

The only advantage of Al Maha departure service is that you are taken to the front of the queue for security otherwise you join the Fasttrack queue.