My shop gets an hours worth of diagnostic charge quoted up front to the customer. If it turns out being a difficult diagnosis, we call the customer to let them know, and they can make up their mind if its worth more money, or to live with it. (95% ok more time) . Not all diagnosis are the same, as is no dental procedure is the same or no doctor visit is the same. Educate our customers to this and life is a lot easier. Being proactive instead of reactive in our industry is a great tool.
It really burns me though that my local parts supplier ( who wants ALL my business and to be 100% loyal to him) reads SES codes for free!!! Talk about biting the hand that feeds you. I know most of his customers are the do-it-yourself type of customers, but it is really hard to explain to my customers why we charge for diagnostics.
Dia charges have always been a battle in our area, there is a local shop that is advertising on the radio "free diagnostics" "no charge to look at your car" in our area right now. I think he is on the ropes big time, and he is spending a lot of advertising dollars to promote free work???? I just dont get it. I guess that is why there are professional shops and the shade tree shops.
I'll stick to my guns on diagnostic charges, if we lower are standards then we are no different than the other 75% of the shops out there.