Manipulating reserve estimates such as the allowance for doubtful accountants or warranty claims is a common method used by fraudsters. If a fraudster wants to artificially increase earnings (NI), how might he or she manipulate a reserve account? 1) Debit the reserve and credit revenue. 2) Credit the reserve and debit expenses. 3) Overestimate the reserve. (Cr. Allowance; Cr. Warranty payable-... 4) Use an unjustified higher percentage of the underlying account in calculating the allowance