@rotarywise:
Allow me to paraphrase you, I would have thought that The holder of an IR(H) valid for a single-engine helicopter type wishing to extend the IR(H) to a multi-engine helicopter type shall satisfactorily complete a course comprising at least 5 hours dual instrument instruction time in that type (JAR–FCL 2.240 (a) (4)) and the absence of "Instrument Rating Skill Test" on the original JAR-FCL was enough of clue for not considering this a prerogative of an IRI(H) job.
The UK CAA seems to have been the one introducing the idea of Skill Test following the 5 hours whereas the original texts, quite interestingly, refer to to IR(H) extension to ME on the Subpart F - Type Rating. Not on the Subpart E - Instrument Rating, isn't that interesting? Instrument instruction explicitly related to a type rating, therefore the job of a type rating instructor. That seems to be quite a clue in IMHO.
But you're right, ultimately what matters isn't our opinions here on this forum but what our issuing authorities decide based on those texts, with coming EASA the margin for interpretation will probably shrink substantially and these debates will probably be happening less and less:roll eyes: