Valuation of stock

stock declared by firms for OD purpose is normally false, as the reason behind it is that if stock is less than 80% margin than OD limit may be cancelled or limit may be reduced, so its the practice to show stock @ 80% margin. in a bank stock statement varification when i visited to a client then i found only rs 600000 stock(Bardana) as against 1.2 crores shown in stock statement.