What is the test for a probation officer to determine a defendant's ability to pay probation costs?

shall determine the amount of payment and the manner in which the payments shall be made to the county, based upon the defendant's ability to pay. The probation officer shall inform the defendant that the defendant is entitled to a hearing[] that includes the right to counsel, in which the court shall make a determination of the defendant's ability to pay and the payment amount. The defendant must waive the right to a determination by the court of his or her ability to pay and the payment amount by a knowing and intelligent waiver." (Stats. 2009, ch. 606, 6) "[A]lthough section 1203.1b permits a separate hearing on a defendant's ability to pay probation costs, the statute does not prohibit a sentencing court from conducting the hearing as part of the sentencing process." (People v. Phillips (1994) 25 Cal.App.4th 62, 70, superseded by statute on other grounds as noted in People v. Valtakis (2003) 105 Cal.App.4th 1066, 1073-1074.)