Priced too low. - New at being an IC

Hello all.  I have been a transcriptionist for many years, but not working for myself as an IC until recently.  I picked up an account with five doctors.  Four of them are fantastic, but the fifth one is problematic.  He doesn't dictate the entire report, but rather wants the MT to copy and paste from old reports.  These are my issues:  It is not just a simple copy and paste.  I need to go back over it and weed out any duplicate/contradicting  information from the new information currently dictated.  Secondly, I don't have the old reports, so that means contacting the office to have them send me the old reports, putting everything on hold, and then going back over the reports at a later time.  The volume is extremely low.  The four doctors who are awesome generate combined less than this doctor.  All combined, it generates me less than 400 a month.  They are only dictating the cases they don't want to do on their electronic system.  If it were more work, I might just cope with it since the other four would make up for this.  However, at the price I gave them, my hourly average is abysmal.  I do not mind the fact that it is a $300 to $400 account because I realize things have changed.  What would be a good way to address this issue?  I need to charge more for this guy, but I feel unprofessional for pricing it too low in the first place.  In the future, I will find a way to hold off on pricing until I see what the dictation is like.  For this one, should I just stick with my original agreement since it was my lack of thinking it through properly?