1) Most people will do the math and shop around. What percentage of the end cost comes from the labour and the parts is not really relevant. However illogical, people will react differently to the same final price if they think they got 'screwed' either on parts or on labor. With the Internet, people know what parts are worth and can quickly figure out what margin is being made. If the margin is inconsistent or too high, then people may get upset. Along the same lines, people can shop around the book time for each job. If you have a lower hourly rate, but charge more hours, people will believe that they are not getting a fair shake.

2) The quality of your work is what differentiates IT from others. You will have an easier time charging a premium for labour because folks have come to realize that this equates to fewer repeat visits & fewer problems down the road.

3) If I may be so bold, here are my recommendations.

(a) Charge a fixed, public and reasonable margin on parts. If you do this, folks will be less incented to buy new parts elsewhere. People will understand that something needs to be charged because you do spend time ordering, stocking, returning parts, warranty work etc.

(b) Continue to quote industry average labour times for jobs.

(c) Charge more for labour. This is IT's best 'product' and the reason why people come back. This will also protect you if people want to source their own new or used parts for whatever reason. If people believe that they are getting a fair deal on parts and job time, I don't think they will mind paying more for a quality experience.