I just charge for my time to come and get myself out of bed which is $50-70. This is purely to cover the ROI on expensive equipments and other variable costs such as petrol ERP, parking, batteries. Not including the intangible cost of spending time with my family or going for drinks with buddies.
Other else is chargeable based on the man-hour spent which is usually takes less than 2-5 mins a picture to touch up- I just let the print shops tan chiak.
Despite knowing how to use PS and design, I remind myself that I am a shooter not a designer thus allowing designer to also tan chiak. Clients are broad range thus we leave it to client to choose what they want for instance shooters for the wedding event itself, DI on prints, large framed prints. Anyways the clients all know that the print shop averagely charges 40 cents for 4R and if they are regulars they can even get down to 25 cents a piece.
Similar to a Professional Security Consultant charge-out rate is $250 to $500 per day and this does not include the physical security or techinal security i.e. the CCTV, Intrusion systems and all. ( That is covered in the Design and System Installation recommended by the Security Consultant's Final Report).
Therefore I stick to the rule of thumb where client is paying for my man-hour and skills rather than prints. Ofcourse I give whatever DI I can. (nice ones la, delete or edit the not too good ones). I dont know any shooters who have a 100% rate of perfect shoots.