I have a 26" Innova and the only time I had my machine serviced is when the drive belt went. Then the manufacturer (in Texas) talked my husband through removing the gear assembly and bobbin race and send it back to the factory for a new belt. When it came back it was up to us to reinstall and time the machine. Most LA owners I have chatted with on line have all learned how to time their machines because most of us aren't capable of removing the machine from the carriage and hauling it somewhere. I think you Viking dealer is feeding you a load of garbage. She may have been doing this for a long time, but there is absolutely no reason to bring LA in for servicing frequently. They are built so the owner can adequately clean it, oil it and do routine maintenance, such as timing. My machine also makes it easy to remove the face plate and get at the needle bar. I routinely oil in there as well, though not required it is recommended.
I don't know about viking machines, but if they require you bring in for servicing that often, you may want to consider upgrading. Viking are mid arms so they are smaller and not as heavy as a LA so maybe they aren't made like the others to self service and maintain.