Details on the Approximation of time

Hi,

Reading the doc it says about timeForRound:
```
timeForRound

Given a NetworkInfo object, it calculates the approximate time the given round will be emitted at (approximate because the network must work together to create the randomness).
```

It would be great if it gave also worst case scenario in both direction or even better a probability distribution on a range of time, so applications can predict accordingly.

I also could not find what to expect on the mainnet, Is it a one minute kind of difference we can expect or a lot more ?
Thanks