I totally, 100% agree. I explain and explain and explain that I will happily work shops into my routes early in the month for a reasonable fee.
It will save them stress and money (I know they are more concerned about the money!). I'm the ONLY shopper within 100 miles, and I know it!
I did a route earlier that took me 200 miles from home. One company had a shop, would have given me a meal while I was on the road, and I asked a reasonable $20. Nope. Well, upshot is, that shop just did not get done. Last day of the month, they called to see if I could work it in. It's 135 miles each way.
Frankly, my opinion is I'm doing THEM a favor doing the shop at $20 -- it's way below my minimum. I was on a route of 22 shops paying $30 each.
The above poster who said "penny wise, pound foolish" is just so very, very spot on!