In Act 3, scene 3, Macbeth sends a third murderer to help the other two murder Banquo and his son. Does the third murderer know as much about Banquo as Macbeth says he does?

Question

From what I see, it seems as if it could go either way. For example, this part:

"Almost a mile, but he does usually -
So all men do - from hence to the palace gate
Make it their walk."

Yes, the third murderer knows something about Banquo....but then again, he says that all men do the same, so then it seems as if he's just saying something everyone would know. Help!