Ian,
When you say 4:1 return, I take it you mean takings on converted quotes.
Isnt the real test, the ratio of enquiries you achieve from an advertising campaign, whether its a YP ad or a Leaflet etc. After all, the marketing is done to get enquiries and then its down to you to convert them into jobs. If you are operating on a low price, you stand a good chance of getting the job by quoting over the phone, but for the higher price you need to go and do an on site quote. You can set that vital first impression, explain the process, create the desire. Obviously if your prices are low, you could still achieve the same ratio of takings done at a higher price, but you would need to do more jobs. If I spent £100 on a good leaflet, self delivered, I would expect a £250 return within a day or two of delivery and up to 20:1 return over one year. YP I find is more around the 4:1 mark for me.
Dave.