this clock really sucks they need to fix. all this latency and this playing is bullshit it's not accurate at all. if you're beating higher than rated players that add seconds to their clock.
From what I can tell it's virtually impossible to add seconds to your own clock, or at least very difficult and extremely (like extremely) uncommon. What might be to blame is clock lag, which effects everyone equally. (I tried this experiment with my friend once) where it seems that the clock although it can keep the right time, displays the wrong time.