An appellant whose parole was revoked only for the same conduct as in his criminal case was entitled to presentence custody credit because he established that the conduct leading to his sentence was the “but for” cause of the presentence custody. In October 2011, appellant was convicted of a violation of Penal Code section 245, subdivision (a)(1) (assault likely to cause great bodily injury) and admitted a prior “strike” crime. The offense occurred on March 11, 2011. On November 17, 2011, he was sentenced to four years in prison. The trial court declined to award presentence credits for most of the 252 days of actual presentence custody time appellant served, finding that the time was not attributable solely to the instant offense but was also based on technical parole violations. Reversed. Appellant was arrested for the instant offense and for violating his parole (in part, for technical violations). He entered an “optional waiver” and subsequently requested a parole revocation hearing, which was held November 3, 2011. At the hearing, appellant admitted that he committed the assault and the other allegations were dismissed. Because appellant’s parole was revoked solely for the conduct underlying his current conviction, he was entitled to presentence credits from the day of his arrest through the day of his sentencing. The court distinguished People v. Stump (2009) 173 Cal.App.4th 1264. The matter was remanded for calculation of appellant’s conduct credits.

The disparate conduct credit calculations resulting from amended Penal Code section 4019, effective October 1, 2011, do not result in a violation of equal protection; further, conduct credits are not calculated under the more favorable formula for the period of custody post October 1, 2011. To provide guidance to the trial court on remand, the court held that no equal protection violation results from excluding appellant from the more favorable conduct credit calculation formula provided by amended Penal Code section 4019. The amendment to the statute dictated prospective only application. Appellant’s equal protection claim did not succeed because prisoners who committed crimes before and after amended section 4019 took effect are not similarly situated. Even assuming that during the period of time that appellant was in presentence custody after October 1, 2011 he was similarly situated to other defendants who committed their crimes after October 1, his equal protection claim still fails. Absent a classification touching on a fundamental interest, there is no equal protection violation if a challenged classification has a rational relationship to a legitimate state purpose. Here, applying amended section 4019 prospectively optimizes the deterrent effect of penal laws by carrying out the original prescribed punishment, rather than permitting a defendant to benefit from a subsequently enacted statute providing for a less harsh penalty. Also, in addressing social ills and funding services, the Legislature can engage in piecemeal approaches to statutory schemes, as illustrated by the many changes in conduct credit earning rates of late, to determine what works. For these reasons, appellant is not entitled to calculation of conduct credits under the amended section 4019 formula for his time in custody before or after the October 1, 2011 effective date of the statute.