Hey Rod. I'm no stranger to these clamp style cookers either. I own 4 of them ranging from 4.5L-10L that I've had about the same amount of time you've had yours. I also own a conventional Fagor 8/4 Duo set that's more trouble then it's worth. Have to admit that these tanks have to be the best pressure cookers ever made and super easy to clean and maintain. Never a problem in all the years. Only thing dangerous about them is the massive weight.
What I'm wondering about is both of these show companies hawk the Magefesa Star and the Fagor Classic in both straight and convex bases using their own brand names such as Supercooker and Pressure Magic respectively as pressure fryers and command prices starting in the $300 range, about double the worldwide fair market value. Both Magefesa and Fagor companies specifically warn against using oil although I've been using them for pressure frying for years without the slightest problem. These two show sales companies are trying to project an image that these are somehow different and special then the off-the-shelf versions. Magefesa USA and Fagor Espana insist that these pressure cookers are unsafe with oil, yet these show companies that parallel import them, sell them as pressure fryers at hyper inflated prices. Examining one of the Fagor's that they sell as a fryer shows absolutely no difference. They're marked as a Classic, same, lower 7.9PSI rating, Same tubular silicone gasket, heavy build,clamping system and clamp riveting, even the blow-off safety is the same. Ditto the Magefesa which is a lighter build version of the Classic, but robust none the less. I can't see a single shred of difference between them except the inflated price. Only thing that I can think of is that you're paying the difference in liablility insurance. As you already know, these things are built to contain a hand grenade, let alone contain hot oil safely.
I just want to know what's the deal with the inflated prices and why the manufactuer's themselves vehemently claim that they are not designed to pressure fry. http://www.accuproinc.com/
Magefesa Star sold as a "Supercooker" http://www.pro-selections.com/
Fagor Classic sold as a "Pressure Magic"