a deep and troubling mystery!

What is the deal with institutional clocks? In the classroom I'm working in this semester, the wall clock has been wrong, differently, every day so far this semester...but always by approximately exact-hour intervals (in other words, it might say 5:11 when it's actually 10:11). The two nearest clocks in the hallway are also incorrect - and different both from one another and from the clock in my room, but also wrong by exact hours.

This is something I've noticed about institutional clocks, in schools, universities, and the like, for years...and it baffles me. In the rest of the world, setting a clock is no big deal: it runs accurately for a good long time, and sure, once in a while someone might forget which way to move it when Daylight Saving Times comes or goes, and so for a while it might be two hours out of whack - but that's easily corrected. What doesn't happen is random, arbitrary shifting of the time such clocks tell.

There seems to be some centralized (or at least distant) control for institutional clocks...since, as I'm sure you've all observed, when they're wrong, sometimes they suddenly start progressing rapidly forward or backward. Presumably someone somewhere is causing this to happen. But that still doesn't explain why such clocks are so prone to going wrong...or why when they do so, they're so often wrong by exact-hour intervals.

One more thing: these are the same kind of clocks whose minute hands creep backwards for a second before advancing...a phenomenon well-known to clock-watching test-takers, causing momentary heart attacks as if they will never get out of that room.