Dee .... if you are that comfortable repairing the newer machines perhaps you can inquire about purchasing the required tool. Figure the cost of the tool divided by the number of times you would have otherwise have taken it to the dealer to see if the tool is cost feasible.
I have a Janome 6600 for 3 years now - but it was purchased as a used machine from the dealer (so it was well serviced before purchase). I've brought it in once (recently) because *I* screwed up the timing on the machine by doing something stupid. BUT I keep my machine very clean (to the extent that I can through the top plate only).
If you keep it clean on a regular basis, you may not need to open it up very often.