Nino can u have a close look at the LE Walking Dead machine u have at your workshop and compare to any other type of flipper mechs or pop bumper mechs and give an opinion if they are the standard accross the industry etc.
That way, it will tell me if the TimeZone machines are sloppy from massive massive usage or if the flipper and pop bumper mechs are just lighter in design than what they used to be ? Or if the design is fine etc.
Your quick study may give some insight to the issue ?

No noticeable difference.

I think the games at Timezone are not suffering from over use at all. All machines need time to settle and they should have been checked by the operator after a month onsite. This sounds like poor design with the flippers and lazy maintenance. The pops should still be good.

What is really annoying is that I've pulled machines out of containers and although they are filthy, they still work. These are less than a year old.

Call the operator - or better still - contact your guy at Stern AND let AMD know. This is really a lousy misrepresentation of pinball.