Gradually increasing might be a few %. The prices given, particularly the two year ones which hike the one year costs by around 40% over the whole term (so the second year costs you 80% more) indicate other factors at work.
Gradually was maybe being generous!!
I was actually referring to getting a quote at one point in time, and getting another at a later point in time, rather than the relative expense of 24/36m contracts compared to 12m. They started low to build excitment/demand/interest in the product, and I suspect are now increasing it based upon what the market is prepared to pay. Makes sense.
24 month and 36 month quotes do appear to be higher than 12 month quotes - some more than others. I think there's a flaw in their logic that could be exploited though. I reckon their quoting system makes assumptions based upon which service will be due next based upon the age and mileage.
This means that if you're confident you'll need a B service and brakes, but the system assumes an A-service only, then the quote will be bargain basement. Of course the opposite is true when quotes appear expensive - it could assume you're due a big one, and you know you've just had one, and so the Service Contract looks expensive.
However the longer the term, then the more likely it is that you'll need expensive services, eg maybe a couple of B services, brake discs/pads, transmission oil, spark plugs, brake fluid, etc in which case the cost spirals!! For example last September (maybe August?) I got the following quotes on the ML270: 12m £82.22, 24m £87.29, 36m £123.71. They can be more certain of big bills over the longer period.
I had several in-depth conversations with my Service Advisor, Service Manager, Principle and indirectly Area Sales Manager about the initial teething problems - mainly because they affected me!! They acknowledged issues around being able to provide consistent quotes, although word is that this is resolved. I also had similar conversation with someone in DCUK - I know one or two other members did too - who seemed to suggest a similar story but from a DCUK rather than MB dealer perspective.