Tea gardens are a customer type of their own
Gardens build and maintain continuously — worker housing, factory buildings, drainage, roads — and they buy on formal terms with a purchase process and a store that logs what arrives. A referenced invoice and a challan naming the vehicle and receiver are what reconcile against their records at month end.
A spread-out district
Gardens and towns are scattered across a wide area, so a delivery may take most of a day on roads that the monsoon affects. The challan carrying the date, vehicle, destination and receiver is the only record that survives that run, and it stays against the party permanently.
Seasonal building around the tea calendar
Construction work in the gardens happens between plucking seasons rather than continuously, which concentrates demand into predictable windows. Movement over the same weeks last year is what the stocking decision should rest on, because the peaks repeat.
Close to the Siliguri corridor
Material moving north and east passes through this belt, and any supply crossing into Sikkim or the north-east changes the tax treatment to IGST. That switches automatically from the buyer's state on the party record, with e-way bill details already captured.