Whether the mean of justice is the real mean?

Objections

Objection 1 : It would seem that the mean of justice is not the real mean. For the generic nature remains entire in each species. Now moral virtue is defined (Ethic. ii, 6) to be "an elective habit which observes the mean fixed, in our regard, by reason." Therefore justice observes the rational and not the real mean.
Objection 2 : Further, in things that are good simply, there is neither excess nor defect, and consequently neither is there a mean; as is clearly the case with the virtues, according to Ethic. ii, 6. Now justice is about things that are good simply, as stated in Ethic. v. Therefore justice does not observe the real mean.
Objection 3 : Further, the reason why the other virtues are said to observe the rational and not the real mean, is because in their case the mean varies according to different persons, since what is too much for one is too little for another (Ethic. ii, 6). Now this is also the case in justice: for one who strikes a prince does not receive the same punishment as one who strikes a private individual. Therefore justice also observes, not the real, but the rational mean.