The most recent issue of Coding Edge specifically addresses this topic on page 19 in the blue box on the right side of the page titled POS = Location Where Patients Receive Service. It states
"Per the Centers for Medicare & Medicaid Services (CMS) Transmittal 2407, the place of service (POS) code for all physicians paid under the Medicare Physician Fee Schedule (MFPS) must match the setting in which the beneficiary receives the face-to-face service. Billable, non face-to-face services (such as when a physician interprets diagnostic test results) are billed to the POS in which the beneficiary received the technical portion of the service."
It also cites an MLN Matters article regarding the subject.
So if the patient did the sleep study at home then your physicians professional interpretation service needs to be billed with POS 12 for the home.
Since the reason for the article was the fact that the POS on claims is on the OIG work plan you definitely want to make sure you are billing the correct POS on all of your claims but since sleep disorder services are also a hot button issue you have a potential double whammy for auditors.
Hope this helps lead you to the information & documentation you need to insure you don't end up in any auditors cross hairs.