With the enactment of the Law on the Reduction of Discretionary Imprisonment Sentences in 2020, the legislator considered distinguishing between similar and dissimilar discretionary offenses and establishing separate criteria for sentencing in each case. However, at the time of adopting the new rule, not only did the legislator once again fail to define "similar offenses" and provide a comprehensive criterion, but the sole approved criterion was also objected to by the Guardian Council and ultimately removed. This study presents and briefly examines the key perspectives of legal doctrine on the matter. However, its primary focus is on analyzing judicial rulings and sessions to identify a criterion for differentiation based on the current judicial practice in the country. The findings reveal that, contrary to expectations, the ambiguity resulting from the legislator’s silence is too extensive to be resolved merely through judicial interpretation and solutions. In this regard, the authors, by reviewing existing legal doctrines, considering current judicial practice, and examining the origins of differentiation as a guide, propose the theory of "unity of fundamental value and punishment." According to this theory, for two or more offenses to be considered similar, the legal values they protect (which lead the legislator to categorize them under a single title or subject) and their prescribed punishments must be equivalent.