I absolutely hate
being stumped -- and I can't lose this problem, so I've been rethinking it.
Penal Code 872.5 provides, "Notwithstanding Article 1 (commencing with Section 1520) of Chapter 2 of Division 11 of the Evidence Code, in a preliminary examination the content of a writing may be proved by an otherwise admissible original or otherwise admissible secondary evidence."
The leading case on this issue is Vanguard Recording Society, Inc. v. Fantasy Records, Inc.
(1972) 24 Cal. App. 3d 410, 418-419 -- where the court permitted use of a summary of 50,000 invoices, which were prepared by Plaintiff's controller. Okay, great. The issue here, then is that these spreadsheets are not
business records. They aren't prepared in the ordinary course of business, so they do not have the necessary indicia of trustworthiness to be admitted over a hearsay objection. Consequently, they are not otherwise admissible secondary evidence, and so Penal Code 872.5 does not except them from the hearsay rule.
The witness can use recollection refreshed-past recollection recorded to read the spreadsheets into the record (Evid. Code 1237(a)) -- assuming that the proper foundation is laid. But, this would definitely keep the spreadsheets themselves out of the record -- and, aggressive cross exam may be able to show that the spreadsheet's author isn't really competent to write a spreadsheet formula (e.g., "How do you add an entire column of numbers using Microsoft Excel?"). Of course, the witness may be computer savvy, and that would ruin your whole day, but at least you have a shot at getting the witness sufficiently confused so that he/she doesn't say, "Oh, that's easy, '=sum(A:A).'".
I feel better now. Good luck.