I. When a vehicle is used to render or deliver commodities in bulk or provide services in terms of weight units, the vendor of the bulk commodities or services shall include with the original invoice to the purchaser a duplicate copy of the weight ticket that represents the actual weighing of the services or bulk commodities; provided, however, that if the purchaser himself carries away his purchase, the vendor shall be required only to give to the purchaser at the time of sale a delivery ticket stating the net weight of the commodity or service.
II. The vendor shall keep and preserve the original weight ticket with the invoice for at least 2 years. Copies of the weight tickets and invoices shall be open for inspection by any weights and measures officer of the state at all reasonable times.