the expression "investment" must be understood according to its common business and commercial usage. In the Notification issued by the State Government and the Rules framed, the requirement was that the investment made by the dealer in plant and machinery in the Small Scale Industrial Unit should would have been less than Rs 5 lakhs. Money spent on upgrading or replacing machinery is investment that would increase the productivity of the machinery and consequently generate further income thus it would be equivalent to acquiring of commodities that generate further income. The expression "investment" in plant and machinery is not subject to the impact of depreciation in the value of plant and machinery. Since the Assessee's investment was more than Rs 5 lakhs before the periods in question and since the investment continues to remain unchanged, the Assessee would not be entitled to get exemption from payment of sales tax either under the Rules or under the notification.