Yes, an interesting difference. That's because 13485 has not moved up to the high level outline like everyone else. 13485 is still based on ISO 9001:2008.
Would it be appropriate the administrators of 13485 are behind the times?
The fact that an ISO Management System Standard follows the High Level Structure, does not mean they cannot add requirements in order to make their document more prescriptive, as they see fit, to deal with the risks they have in their context.
As an example, ISO 37001:2016 (Anti-bribery Management System) follows the ISO HLS document. In the section that deals with Internal Audits, it requires the following, way above and beyond the requirements from the HLS:
9.2.4 To ensure the objectivity and impartiality of these audit programmes, the organization shall ensure that these audits are undertaken by one of the following:
a) an independent function or personnel established or appointed for this process; or
b) the anti-bribery compliance function (unless the scope of the audit includes an evaluation of the anti-bribery management system itself, or similar work for which the anti-bribery compliance function is responsible); or
c) an appropriate person from a department or function other than the one being audited; or
d) an appropriate third party; or
e) a group comprising any of a) to d).
The organization shall ensure that no auditor is auditing his or her own area of work.
NOTE See Clause A.16 for guidance.
As I said, just one example of an ISO HLS-based standard that
EXPLICITLY prohibits people from auditing their own work. Very likely, the ISO TC 210 will keep a similar stance in the future version of ISO 13485.