it is normal for floating point numbers to have tiny variations like that, so rounding whenever you check the global variable is usually necessary.
the event sheet runs at the games frame rate - normally 60 times a second under ideal conditions.
that is every 0.0167 seconds. And there is no guarantee that each tick will happen at an exact interval.
you have to use dt to know how long it has been since the last tick.
looking for a specific time with that many decimals will not work.
you can use timers, and other types of triggers to make things happen when required. What are you trying to do? there may be a better way that you haven't considered...