For me, it may be that the toilet paper roll needs to have the open end away from the wall. I don’t want to reach under the roll to take a piece! That’s ludicrous!
That or my recent addiction to correcting people when they use “less” when they should use “fewer”
That sounds a little bit like a language barrier type deal but that does make more sense to me too, since you are prefacing the Saturday with a unit of time to measure by “week”
It’s really just a shortening of “a week from Saturday”, so more of a dialect than language thing.