Medicare pays for physical therapy, occupational therapy, or speech-language pathology services as posthospital SNF care if they are furnished—

(a) By (or under arrangements made by) the facility and billed by (or through) the facility;

(b) By qualified physical therapists, physical therapist assistants, occupational therapists, occupational therapy assistants, or speech-language pathologists as defined in part 484 of this chapter; and

(c) In accordance with a plan that meets the requirements of § 409.17(b) through (d) of this part.