Canada Roll Hunting Question

I live in Toronto, Canada. In the year that I've been withdrawing coin rolls from the bank, for coin roll hunting, and I've noticed that there are two types of rolls that can be withdrawn. The first type of roll is like paper, with tighter crimps on the ends, which I assume are machine wrapped. The second kind are the customer wrapped rolls, which are generally more crudely crimped on the ends with darker paper quality. From my experiences, it seems that the customer wrapped rolls yield better results in terms of finding silver and nickel, while machine wrapped rolls have never contained a keeper. As a result, I have the following questions:
From your experiences, do customer wrapped rolls yield better results?
Is it possible to find silver or nickel in machine wrapped rolls?
Does the bank take all silver and nickel coins, in accordance to the alloy recovery program, prior to wrapping them in machines?