Only you know how much of a fee (increase) to charge, for only you know the magnitude of the work and assembled data that describe the true nature between these two reports. Did I say "two" reports ? I meant "two" assignments. So, I guess you charge your normal fee for the 2055-Exterior, and then you charge your normal fee for the 1004-Full, and hopefully your client will understand that they have to KNOW what they want, and they have to take RESPONSIBILITY for what they order. You have not revealed the depth and quality of the client relationship that is in place, and this may be the very crux for why there is a quandry about the mis-ordered order, and the fee issue, because there may be an assumption that the appraiser is always supposed to be willing to lose money when fulfilling subtle faux pas by the client. They may also be speaking of much future work in your area, and this element also plays into the overall decision process. I am certain that if you explain your side of the matter clearly, they will realize that you are a fair and reasonable person....and you can have the outcome that you desire without putting a dent in this working relationship.