Ok thanks makes kind of sense..But has it always been designed this way?
It cant be changed?
I was reading there was some error in the script that kind of implied there was no limit, or the amount could be changed?
I just did a little digging on this. It seems you were right and there is not hard limit of 100 billion coins, it's more of a theoretical limited but the coin is actually coded in away that allows up to a 5% inflation in the first year after block 600,000; and the inflation tappers off every year thereafter (max amount of coins that can be mined in a year after block 600,000 is 5,256,000,000, but will most certainly be less due to the randomness of the block rewards).
There's an interesting discussion on this here:
https://github.com/dogecoin/dogecoin/issues/23