It is clear that this issue has caused at lot of confusion and expense.
It is true that the cost and change to the industry has been considerable, and unfortunately these extra costs do have to be passed on to the customer, either by a general increase in costs, or as a specific charge for the service.
However, it appears CAMOs have a very varied way of charging, and indeed how they conduct their busines, and I feel that a lot of scare-mongering has gone on.
The Part M system is nothing significantly new. Aircraft have to be maintained, to an approved schedule (sorry programme!), and their paperwork has to be kept current for the CofA to be valid. Nothing new here.
The 'controlled environment' and having an aircraft 'managed' is only new by allowing an organisation to be specifically approved for this purpose, where as before the owner/operator was completely responsible for the continued airworthiness of their aircraft. The actual task of this 'management' is not all that difficult, but for a CAMO to do it there has to be a contract in place between that CAMO and the aircraft owner/operator and much time has to be spent by the CAMO in keeping logs up to date, informaing owners when/what maintenance is due - lots of time pushing around paperwork.
Owners have a choice. You can have someone (a CAMO) manage your aircraft, in which case you have to pay, or you can do the task yourself, in which case the aircraft falls into an 'uncontrolled environment'.
For an aircraft kept in an 'uncontrolled environment' the ARC has to be renewed at year following an Airworthiness Review. The ARC cannot be extended (as it can be if the aircraft is fully compliant within a controlled environment, however the ARC can only be extended twice, so each third year requires the full Airworthiness Review').
The Airworthiness Review is not a particularly great task, but does require the CAMO to survey the aircraft, and fully review all the paperwork for the aircraft, including the Flight Manual, docs, TCDS, recent maintenance records etc. The full Airworthiness Directive compliance has to be established, as well as the status of life limited components, modifications, repairs and maintenance. However, again, nothing is new here - this has always been required for an Annual (was all in the old LAMS schedule), and had to be confirmed to the CAA for the old COfA renewal (Star Annual). So if a company has known an aircraft for a period of time they should already have this information properly recorded, otherwise they haven't done it right in years gone by.
For an aircraft new to a CAMO, it doesn't take all that long to establish it's compliance (provided the owner provides the relevant logs/docs), but it's often found that work has to be done to make it complaint (from replacing missing placards, sorting out missed ADs to replacing out-of-life parts etc) albeit these issues should have been resolved under the old system, unless an issue had arisen between maintenance inspections.
For most private use aircraft, I firmly believe, that the 'uncontrolled environment' is the most cost effective way forward. Yes you have to do the AR every year, but the cost of this (especially if done at the same time as a annual when the aircraft is already opened for inspection) is less than the cost of the management service. Typically management costs between £500-1000pa, whereas the Airworthiness Review and ARC renewal is being charged at a few hundred pounds - do the math! (The fees payable to CAA for the ARC validity is the same regardless of how the aircraft is managed).
If anyone has a specific quiery then you can PM me. And yes I am a Licenced Engineer and ARC signatory working for a Part M approved company (F&G, and M3 for you non-EASA bods), currently overseeing around 125 EASA aircraft.