The binary notation of Certification (Category A or B) does not provide a rich enough vocabulary to describe operations - that is why the ICAO Heliops Panel devised the Performance Classes.
The Performance Classes adopted the purity of performance inherent ICAO Annex 6 Part I with engine failure accountability. This included, in the specification of PC 2 and 3, a requirement to perform a safe-forced-landing should an engine fail (exactly as in Annex 6 Part I): in the take-off and landing phases of PC2; and the whole flight envelope of PC3. At the time of provision of the Second Edition of Annex 6 Part III in July 1990, the performance classes were harmonised with the Certification Standards.
However, life is never than simple and by 1998, the ICAO Standards produced by the Heliops Panel, with respect to performance, were beginning to be seen as ‘somewhat aspirational’ and based upon a projection of the development of helicopters that had not (and might not) come to fruition (the same projections had been used by the FAA in NPRM 80-25). As JAR-OPS was the first attempt at providing a regulation in compliance with ICAO, it was the JAA States which established that projections made by the Heliops Panel were not being (and were unlikely, in the near future, to be) realised and adjustments became necessary (the introduction of risk assessed exposure).
The concept of ‘defined’ exposure was formulated by the JAA, risk assessed, presented at Board level, and published for general comment. Following acceptance by the members of the JAA, the necessary changes were made to JAR-OPS; ICAO was informed of the resulting differences and a proposal was put to the ANC for a revision to Annex 6 Part III - to bring States back into compliance. In 2002, the ICAO HTSG was formed and tasked with this revision.
The net effect of these changes were to separate Operational from Certification Standards. The risk assessed procedures used in offshore (and operations with exposure onshore) when operating outside PC 1, no longer fitted into the neat categorisation of A and B. However, as Dino has pointed out, this required operational regulations to derogate from the HV Limitation - applicable to helicopters with more than nine seats.
The point of this is that a helicopter with more than nine seats and operating with exposure, is neither operating in accordance with the procedures/profiles of Category A nor Category B. However in Europe, they are operating quite legally within the requirements of EASA Part CAT.
Where there may be an issue is in another jurisdiction where the helicopter with more than nine seats is Certificated in Category A - in accordance with Part 29 - and operating offshore (or onshore with exposure) but where the State has not made adequate provisions in its regulations for such operations.
Jim