Kautilya's Arthashastra 2.7.18

2.7.18

āyavyayanīvīnām agrāṇi śrutvā nīvīm avahārayet //

When they (the accountants of different districts) present themselves with sealed books, commodities and net revenue, they shall all be kept apart in one place so that they cannot carry on conversation with each other. Having heard from them the totals of receipts, expenditure, and net revenue, the net amount shall be received.