Power and coal contractors
Thermal and mining operations bring contractors working to audited terms with purchase orders and gate registers. An invoice carrying both GSTINs, HSN codes, line-wise tax and the PO reference is what clears, and the challan reconciles against their store.
A border location
Singrauli sits against the Uttar Pradesh boundary and supply crosses it routinely, which changes the tax treatment to IGST. That switches automatically from the buyer's state on the party, with the e-way bill details on the delivery record.
Long payment cycles
A contractor working for a large operation is paid when their process releases it, which is rarely quick. Ageing rather than totals tells you where you stand, and a limit per contractor keeps exposure inside what you can carry.