I think you have 2 threads in here. This was my answer.
We use for all psych evals 90791 without medical services( ie medications) or 90792 with medical services (ie LABS and/or to review, continue, increase a dose, decrease a dose, add a new medication, or stop a medication). A psych eval can be coded more than once for some payers on an established patient. Example would be the severity putting the patient in the hospital and upon discharge an evaluation is done for additional new diagnosis effecting current and/or change in care. For follow-up visits for medication management only the level of service by MDM 99212-99215, if they provided the additional psychotherapy of 16 or more minutes, I add the add on codes 90833, 90836, or 90838. We are RHC so we use T1015 for APRN-CNP's, and for all LSCW's or LCPC's T1040 (90832, 90834, or 90837 with modifiers AJ, AH, or HO) with the CPT's listed second. We bill the T1015's and T1040's on separate claims.