I re-read the text you reccomended. I guess I was wrong in my previous post, when I said that only one device an be commanded.
The level shifter mounted on I2C works on the 2 wires of the single I2C, and since he slaves are indentified by their unique addresses, like in the case without shifter, they can share the same I2C. So no need for more channels in the case of I2C. Assuming the shifter can handle the current of 2 or even three sensors (in my case).
I am very interested in this shifter because it is cheap. Burning 1-3 bucks ("for a buck")is one thing, and burning 20 - another thing.
There are other shifters "on 8 bits" - whatever that means and 4 channels ones (which I imagine are designed for digital pins). All cost 3-4 times more than this one.