Advance tax obligation: taxpayer may submit Form 28A when disputing officer's estimate, or pay per own computation. Assessing Officers may order payment of advance tax; an assessee who views the officer's estimate as excessive may submit an independent estimation and the amount payable in Form 28A to the Assessing Officer. If the assessee's own tax computation exceeds the officer's demand, the assessee should pay advance tax according to the assessee's computation without needing to notify the Assessing Officer.