Scrutiny of returns: officer may seek explanations for discrepancies and initiate assessment or enforcement if no satisfactory reply. The proper officer may scrutinize a registered person's return and related particulars, notify discrepancies in the prescribed manner and seek an explanation. If the explanation is accepted, no further action is taken. If no satisfactory explanation is furnished within thirty days (or such further period as permitted), or if the person accepts discrepancies but fails to correct them in the subsequent return, the proper officer may initiate assessment, enforcement measures, or determine tax and other dues under the statute.