the buy zone, page-9

I've been trying to make sense of some of the numbers in the most recent report and presentation.
I believe there's a bit of discrepancy between the sales prices and forecasts mentioned. I'm hoping that the sales price forecasts have actually been under quoted and that we are yet to see a much better upside.

So on page 7 of the presentation it mentions that the 2018 product mix was made up of approximately 20% course and 80% fine flakes.
If we look at the graph showing the 2018 product price range achieved on page 19. We see the following:
Fine flake $375-700
Course flake $550-1900
if we work backwards and assume a conservative price of $375/t for fine flake graphite:
we get an average price of $1500/t for course flake graphite (80x375/20 = 1500)
Now on page 24 the outlook suggests that the product mix for 2019 will be trending to the target 70%fine and 30%course.
Yet they mention the weighted average price is $500-600 trending towards >$600/t
However, from the above worked out prices, assuming that they do not change at all (so again conservative).
We have ($375x70+$1500x30)/100 = $712.5/t

So without any increase in price of graphite in 2019 we can assume a weighted average price of $712.5. There's a big difference between this and the >$600/t they have forecast. The $112/t difference amounts to approximately $28mil when production hits 250ktpa.

I just hope they are being conservative in their forecast and that we will get a nice surprise.