When business records must be reconstructed with a taxpayer, you should

Keep a copy of the written records with the office file. You'll be able to remember where the figures came from.

• Give the written reconstruction back to the taxpayer with their tax return. There's no need to keep a copy with the office file because it's the taxpayer's responsibility to keep those records. 
• Keep a copy of the written records and make detailed notes about how you arrived at the figures for gross receipts and ea of the expenses, then give the original copy back to the taxpayer.
• Keep a note with the tax return saying that the records were reconstructed.