Cal. RTC § 20645.5

(a) If a postponement claim under Chapter 2 (commencing with Section 20581), Chapter 3.3 (commencing with Section 20639), or Chapter 3.5 (commencing with Section 20640) is received by the Controller by February 10 for the fiscal year in which postponement is being claimed or by another date set by the Controller pursuant to Section 20622, then any delinquent penalties, costs, fees, and interest accrued for that fiscal year shall be canceled unless the failure to perfect the claim was due to willful neglect on the part of the claimant or representative.

(b) In the event of willful neglect, a payment from the Controller for that current fiscal year can be used to pay delinquent taxes only if accompanied by sufficient amounts to pay all of the delinquent penalties, costs, fees, and interest. If an amount sufficient to pay all of the delinquent penalties, costs, fees, and interest is not received by the tax collector within 30 days from the date of the payment from the Controller, the tax collector may return the payment to the Controller to deny the postponement claim.

(c) (1) The Controller shall notify the claimant in writing when the payment has been submitted to the tax collector.

(2) In the event of willful neglect, in addition to the information required pursuant to paragraph (1), the Controller shall also notify the claimant in writing and provide a copy of the notification to the tax collector that a payment amount sufficient to pay all of the delinquent penalties, costs, fees, and interest must be received by the tax collector within 30 days from the date of the payment from the Controller to the county and that if this payment is not received by the tax collector, the tax collector may return the payment to the Controller to deny the postponement claim.