Form 1120 Cash-Basis Revenue & Expense Reconciliation When multiple source documents conflict (invoice dates vs. bank deposits, expense ledgers vs. bank statements), establish a single authoritative source — typically the expense sheet derived from actual bank activity, since cash-method corporations report when cash lands in the account, not when invoiced. Map each line item from the authoritative expense sheet directly to Form 1120 line items, flagging book-tax differences (like imputed interest under §7872). Verify Schedule L beginning-of-year balances against prior returns or reconstruct…