As a successful HIMS to BasicMed transitionee, I’ll weigh in on this.
Aside from them pertaining to drug/alcohol, or other mental health concerns, HIMS special issuances are no different from any other special issuance. To grant them special treatment would be to make them a punitive measure. But the HIMS AMEs don’t want you to know this.
Even the BasicMed website states you only need the one time authorization for substance abuse/dependence before you’re eligible for BasicMed.
To require the airman to stay on a medical certificate while operating on BasicMed defeats the purpose of BasicMed. Congress did not want that, and Congress overrules the FAA.
HIMS is covered by Domingo because there is no published interpretation to the contrary. Where people mess up is that when the special issuance medical certificate expires, the airmen has a responsibility to demonstrate that he/she remains qualified for a special issuance medical certificate at the time that the special issuance medical certificate expires. This requires the airman to send in the information required by the Special Issuance Authorization at the time the certificate expires. Some airmen fail to do this. They feel that the certificate is already expired so that last bit of information isn’t necessary. But you need to show compliance with the Authorization up to and through the “Not Valid For Any Class After” date on your special issuance medical certificate.
Treat it like any other follow up appointment. Just don’t fill out a MedXpress application. This results in a renewal and you’re bound to the terms of the Authorization.
Lastly, write a letter to your AME revoking any and all authorization to share information with the FAA until such time that you decide to renew the medical certificate.