Grade decides the rate
Heavy melting scrap, turnings, sheet cuttings and cast are different grades at different rates, and mixing them in one item makes both the purchase and the sale untrackable. Each grade as its own item means you can see what you bought at, what you sold at, and where the margin on each actually is — which in a trade this thin is the whole business.
Weighbridge and the record
Every transaction rests on a weight, and a disputed weight is a disputed bill. Recording the weighbridge slip reference and the gross, tare and net on the purchase and the sale is what settles that conversation. It also gives you a running record you can reconcile against the yard, which is the only way a scrap stock figure means anything.
Rates that move daily
Scrap rates change with the mills and with the market, and buying today at yesterday's rate is a straight loss. Holding the rate on the item and updating it each morning applies it to every purchase and sale afterwards, and per-party rates handle the regular sellers who have negotiated terms. Overrides are recorded, so a rate given on the day stays visible.
Both sides of the ledger
A scrap dealer pays many small sellers and is paid by a few large buyers, which means payables and receivables both matter and they behave completely differently. Seeing both with their ageing is the real picture of the business — cash going out daily against money coming in on a mill's payment cycle is exactly the squeeze that catches dealers out.