What is the test for imposing a minimum and maximum restitution fine on a convicted criminal under the California Criminal Code?

"In every case where a person is convicted of a crime, the court shall impose a separate and additional restitution fine, unless it finds compelling and extraordinary reasons for not doing so and states those reasons on the record." (Pen. Code, 1202.4, subd. (b).) "The restitution fine shall be set at the discretion of the court and commensurate with the seriousness of the offense." (Id., subd. (b)(1).) The statute sets forth the minimum and maximum fine available. (Ibid.) In addition, the court must impose a parole revocation restitution fine in the same amount as the restitution fine. (Pen. Code, 1202.45, subd. (a).) "It is well established that the imposition of restitution fines constitutes punishment, and therefore is subject to the proscriptions of the ex post facto clause and other constitutional provisions." (People v. Souza (2012) 54 Cal.4th 90, 143.) A trial court violates the ex post facto clause if it imposes a restitution fine in the minimum or maximum amount applicable at the time of sentencing instead of a lesser amount applicable at the time of the offense. (Ibid.)