Reopening beyond four years may be sustained where subsequent...

Reopening beyond four years may be sustained where subsequent survey information indicates bogus purchase and sale transactions and the original assessment did not examine those transactions. Production of records does not establish full and true disclosure when the transactions themselves are allegedly non-genuine, and fresh information with a live nexus to income escaping assessment is not a change of opinion. For unproved business transactions, banking-channel payments alone do not prove genuineness without evidence of physical movement of goods. Where both purchases and corresponding sales are treated as bogus, income should be estimated by applying a gross-profit rate to turnover rather than adding the entire purchases, with credit for profit already disclosed.