ox-charts
Reading the numbers

Lots vs units

The UI counts lots; the broker receives units. `1 lot (30)` means one lot of thirty.

You pick2 lots× lot size30 (NIFTY BANK)Broker gets60 units
What you pick, and what the broker receives.

Index derivatives trade in exchange-set lots. Every quantity you choose (the quote row, the ticket, the "+" menu, the replay bar, a strategy's qty) counts lots and shows the units beside them: 2 lots (60).

WhereCounts
Quote row, ticket, "+" menu, replay barLots, units in brackets
Strategy qty and default_qty_valueLots
Risk limits (max lots, max position)Lots
Your broker (placeOrder)Units
Order labels, the panel's Qty columnsUnits, shown as lots when they divide evenly

When there is no lot size

The lot size is the symbol's own, from the datafeed (SymbolInfo.lotSize): NIFTY trades in lots of 75, USD/INR in lots of 1,000 on the same grid. A symbol without a lot size (cash equities, for example) trades in plain units, and every surface shows a plain number. Until the datafeed has told the chart a symbol's lot size, that symbol cannot be traded: the buttons are disabled and say why.