"Do not use “must” as an alternative for “shall”. This avoids confusion between the requirements of a document and external constraints (see 7.6)."
Even though this profile is not (yet) a formal ISO document, do please switch from "MUST" to "SHALL" (ISO doesn't require all caps, but it probably won't mind).
IETF RFC 2119 allows either MUST, "REQUIRED" or "SHALL".
ISO requires "shall"
"Do not use “must” as an alternative for “shall”. This avoids confusion between the requirements of a document and external constraints (see 7.6)."
Even though this profile is not (yet) a formal ISO document, do please switch from "MUST" to "SHALL" (ISO doesn't require all caps, but it probably won't mind).