Most salespeople think price is way more important than it really is. If you are selling a true commodity like materials sure it is. If I'm buying a certain brand of material sure I'm not going to put much more thought into except price. A service like a contractor offer's it totally different. Most cases the price is more important to the seller than the buyer of a service.
I've been asked a few times for an example proposal and what they should look like. It's amazing how many contractors fail at customizing a proposal that sell's the job for them. Most use a standard quickbooks template with some item costs on it. This might work if you are a sub-contractor working for GC's and doing new construction work. For the rest of the customer base this is a huge mistake.
I know most of you are wondering what's the difference between the two? There is a huge difference between them, and this is one of the biggest error's contractors can make and it can cost you your profit and then some depending on the size of your operation. Selling a job using a percentage markup is fine but you need to make sure you understand what gross profit is.