March QTR Result, page-21

The table below applies the average AUD metal prices for the March quarter to today's production update. The formula worked well for the Mar-Jun-Sep 2018 quarters, but went awry last quarter. The reason may be as simple as the spot prices at the time of sale/shipment. There's a large range between the min and max prices each quarter, so timing could make a considerable difference.

In any case, it seems likely there will be a substantial increase in revenue this quarter. Note also that only 90% of production was sold last quarter (Q2 FY19) and 89% the previous quarter (Q1 FY19). Coupled with this quarter's increased production, the sales tonnage could potentially exceed expectation in the upcoming 4C.

In Q2 FY18, 90% of production was sold. In Q3 FY18, 109% of production was sold. In Q4 FY19. 99% of production was sold. It does seem to balance out eventually.