This article contains introduction into whole-society problem of proportionality analysis of financial law acts and deals with issue of clearly too succinct reasoning in constitutional review of financial law cases especially concerning field of political questioning and doctrine of self-restraint in opposition to borders of entropy in a legislative process. Contribution primarily elaborates one of the main subbranch of financial law, tax law. The main aim of the paper is to show de lege lata condition of limits and options of constitutionality review of financial law acts and to assess using of special proportionality analysis in that specific area of law.