You are right, it is very simple. However, I told my audiologist that I wanted Sensaphonics to make me "full shells" as she was the one who sent in the order to Sensaphonics, but I wound up receiving the "regular shells". My advice is no matter what, verify with Sensaphonics (don't just rely on the middle-man/woman) to make sure they are creating the type of shell you want.
Definitely gotta make sure the audiologist knows what you mean. I got lucky in that the place I went to dealt with Sensaphonics a bunch and the one dude used to work in Chicago with them to some degree, so he knew exactly what was going on.