The conformance target definitions in 9 Conformance share the form:
"...SHALL comply with all the CAMP ***** or ***** mandatory requirements listed in this specification, as summaried in Appendix C.1, "Mandatory Statements"."
Despite in invocation of RFC 2119, which provides levels of expectations for interchange in 1.6.2, the only expectation invoked by these conformance targets are with the keyword SHALL.
That is to say that the conformance requirements defined in Appendix C.2 Non-Mandatory, are discarded and rendered nugatory by this definition of conformance targets. Why SHOULD and MAY requirements are defined only to be ignored isn't clear.
SHOULD and MAY carry less force than SHALL but for interchange purposes, are not valueless.