S.145: Method of accounting-Project-completion method-Real estate developer-Sale proceeds recognised only upon obtaining completion certificate and handing over possession, not during year under consideration-No sales effected or possession handed over during relevant year-Ad hoc addition based on registration of sale deeds not justified-Allocation of common expenses among group companies based on business volume accepted by Department in earlier years-Project-completion method regularly followed-No discrepancy pointed out in audited accounts-Ad hoc disallowance not justified. [S. 43CA ,143(3)]