The intent of amendment of the art. 20 of d.P.R. no. 131/86 (T.U. Registry Tax), firstly through the art. 1, p. 87, of Law no. 205/2017 and then with art. 1, p. 1084, of Law no. 145/2018, was to bound the practice of Tax Authorities of qualifying differently the effects of the acts notarized, for the redetermination of the higher registration taxes. Two recent judgments, in the renewable energy sector, give us the opportunity to evaluate the process of requalification of contracts (in accordance with the art. 20 before the adaptations), but above all consider how the case law marks the boundaries of the Tax Authorities action.