Ever notice how car finishes today are less durable than years past? Modern finishes are softer and less durable because of environmental standards which have caused these finishes to be reformulated with less harsh chemicals. I suspect the clear coating used on modern machines has also been affected in this regard. And playfields today are much more glossy than vintage machines so dimpling will show up more. And the speed of the balls, airballs, VUK's and various drops are all going to cause issues. These aren't museum machines, they are meant to make money for commercial placement. Keep things clean and waxed and don't sweat it. It's all about having fun.