Street 6, for instance: I've found it twice so far.
But they're still distinct, in that one Street 6 is within Block M 3 B, and another is within Block M 7.
Which appears to suggest that blocks are more important at identifying an address than a street name is, and if that's the case then that works just fine.
And indeed, a distinct address appears to be something like this: Plot 15, Block M 7 Lake City, Lahore, Pakistan. Plug that into Google Maps and you'll see what I'm seeing (and note that the string doesn't include a street name at all).
It does seem weird to my wee little Ohio-trained brain to identify a building by what block it is on more than the street it is facing, but then: Canadian post codes and Hungarian addresses also look weird to me, and also work fine in the places where they're used.