I've seen before with this. Maybe can you explain in Ethereum form? let's say the average block time are 10 ~ 13 seconds. per confirmation will be 10 ~ 13 seconds as well right?
I think you are confused between different confirmations; there is a difference between a confirmation for a transaction and a confirmation for a mined block. Same process for Ethereum and every other altcoins with different average times.
The explanation above is pretty clear.