The use of a sim depends much on whether one needs to actually learn IFR procedures
What I can see a sim being good for is knocking off legit loggable hours, for somebody who is already checkride ready before they reach the 50hr mark.
I agree in an FAA course, but not in a JAA one. The latter has much more emphasis on a specific set of training routes and approaches and the little tricks and gotchas associated with them. Much easier to practice first in the sim. So if you do need to learn IFR procedures, then the Sim is useful. And if you don't, then you are good enough to only need the minimum time in the aircraft anyway, so the Sim is quicker and cheaper.
the following two cases
- training in a sim and doing the checkride in a real plane
- training in one's own plane and doing the checkride in a different plane
I refered to the FNPT2 in the JAA context. Those two scenarios are never going to happen. You integrate the Sim with aircraft training. You are never going to "train in a sim" and then "do the checkride in a real plane". You'll transition to training in the real plane for at least the last 10hrs. Likewise with your 2nd example, you won't get a JAA F170A or an FAA Instructor endorsement to do a test in an airplane you haven't done enough training in.
Any decent JAA school will have an FNPT2 which is representative of the cockpit and avionics of the training aircraft - I agree though, that this will be less representative if you do it on a SEP, especially if it's your own. But if you own your own SEP, then there is probably little to save going to an FNPT2. (but in your own aircraft you'll be clocking up IAPs at £50 a go, zero in the sim)
It's simply that the cost and effort of the JAA 50/55hrs is significantly reduced by using an FNPT2 in most cases, or the 15hr conversion for that matter.
Currency on type is most of the trick in this game, IMHO
We are talking light pistons here, not jets. IMHO currency on type is pretty neutralised by the time you have 10hrs or so on a training aircraft. I may lack finesse, but I find all (typical not exotic) light aircraft fly pretty much the same, you just have some different settings and speeds to learn and a few variations in procedures/checks for starting, fuel pumps etc. Basic stuff if you are going for an IR.
I was sitting in a fairly fancy professional sim a few weeks ago, with an FMS, 2xG430. Used for training ATP candidates, JAA country. It's far removed from an aircraft in which a checkride will be flown.
Was that because it was the MCC trainer used for the MCC course
after the IR checkride? Most FNPT2s used for IR training are very similar to the school's training aircraft.