In City of Los Angeles v. Retlaw Enterprises, Inc. (1976) 16 Cal.3d 473, the court held that the use of such an adjustment procedure was also proper in considering admissions of prior sales of the condemned property under section 815. "The test for the admissibility of sales of the subject property under section 815 is substantially identical to that for the admissibility of comparable properties under section 816: sales are admissible when they illuminate the value of the subject property at the date of valuation." (Id. at p. 483.)