I think you should read David's post again fella.
What's the point of paying someone to do it when you lose so much.
If you're busy cleaning windows you're far better employing someone to do the window cleaning
Which will free up your time then you can focus on canvassing
I tend to agree with you. If the O/P has spare time to add more customer's to his round, then he has time
now to canvass for them.
But we haven't considered that the O/P may not feel confident enough to knock doors himself. Some people, including some salesmen, view the word "no" as a negative rather than a positive. We had a salesman once who worked out that he got 11 'no's' to one 'yes.' So he welcomed each 'no' as it got him closer to a 'yes.' One of the most motivated guys I've come across.
He could also be in that difficult time where he has a full schedule and wants to employ. He may have too much work for himself but not enough for two. I was in that position when son and later son in law joined me.
I ended up handing over most of my work and working to increase our customer base for me. Tough time for a couple of months but its amasing how much add on work you can find within your existing customer base.