Its just a matter of time until the coin will hit a major exchange and the price will go up minimum by x20
yeah price so stable right now at 2xx sat
when it list major exchange go to 2xxx-5xxx sat
Thats what I like about it, doesn't care about BTCs bullrun

what is the formula or example of calculation for the possibility time to get a reward in POS?
There is not really a easy and direct "formula" for that.
Here is an calculator I've written which gives you the % chance of how long it could take give a specific amount in a transaction.
The code and calculation is also visible.
http://crofly.bplaced.net/