It's hard to know without more information. What payer have you submitted to? You may need to look into what the payers medical criteria is and file an appeal to justify more than 1 unit. It could also be that you should bill the code once per day. For instance, instead of billing with three units, 1 unit for each DOS. In addition, isn't this an add on code? I'm not a coder, so I can't be sure, but the information I'm finding online suggests this might be true... It's for when additional time reading the EEG is needed? Perhaps you've billed it along with another code? In that instance, you would most definitely need to appeal with records to show the additional units are justified.