With the enactment of Law No. 13.670/2018, companies that have adopted the monthly advance payments under the actual profit tax regimeRegime de Tributação pelo Lucro Real) are no longer authorized to offset IRPJ/CSLL monthly payments with federal taxes credits, through the presentation of Electronic Request for Tax Refund and Declaration of Tax OffsettingPedido Eletrônico de Restituição e Declaração de Compensação – “PER/DCOMP”).
Such prohibition, during this time of economic and political crisis, aims to anticipate the Federal Government cash flow with the payment of debts in cash, given that the total corporate income taxes due will be adjusted by the taxpayer in the end of the year.
As this change came into effect in 05/30/2018date of the publication of Law No. 13.670/2018), there was a violation of the vested right, because since January of this year, the taxpayer made the choice to anticipate IRPJ/CSLL debts based on monthly estimative throughout the entire yearand not on a quarterly basis, which still allows the offsetting of debts)  , acquiring the right to pay monthly installments through offsetting.
Note that the option exercised in January 2018 is irreversible by an act of lawarticle 3º, Law No. 9.430/96). Therefore, during the entire tax year of 2018, taxpayers cannot change from the monthly tax calculation for the quarterly option. Likewise, during the same tax year, the Government cannot promote changes in the rules in force at the outset, under penalty of violation of the principles of legal certainty and non-retroactivity of the law prohibited by the Federal Constitution.
It is under this scenario that decisions are being granted by the Judiciary, assuring to the taxpayers the right to continue paying their monthly IRPJ/CSLL estimative debts by offsettingPER/DCOMP).
Therefore, those taxpayers who feel aggrieved by the prohibition promoted by Law No. 13.670/2018 should seek their legal counsel to find measures to ensure their right to continue offsetting the monthly installments of IRPJ / CSLL in 2018.
Candido Martins is available for any clarification on the subject.