Four steps, and you can check every one of them afterwards.
Your lorry crosses the weighbridge loaded, and again empty. The difference is the net weight, and it is printed on your ticket before anything else happens.
A sample goes to the lab. Wet paddy weighs more than it is worth, so a deduction is taken against a published slab. You see the moisture reading and the deduction, not just the answer.
Net weight, less the deduction, times the rate agreed at the gate. The rate depends on the variety and the moisture. Nobody quotes you a number before the paddy is tested.