My point is why does it matter whether they produce 5.0%, 5.5%...

My point is why does it matter whether they produce 5.0%, 5.5% or 6% assuming the price adjustment is linear. What you want is maximum margin irrespective of final grade.

As far as bench tests go, I have seen thousands of these in lithium and while you try and simulate every possible variation (noting no ore body is truly homogeneous otherwise why bother with 100s of tests) they are highly controlled, small sample size bench tests. Representative yes but never 100%.

There are at least a dozen improvements they've made over and above incumbent producers, all well known and which should yield superior results all round.

At the of the day, if 5.5% gives them the highest margin, go for it. So long as your product is within offtake spec, both grade and impurities, you do not attract penalties. What the offtaker is paying for is lithia units, and hence the pricing reflects that in a linear basis (note this hasn't always been the case but is now). Impurities being off-spec increase the downstream refining costs for the offtaker, to remove higher amount of impurities hence the typical penalties should apply if out of spec, to compensate. Tolerances are usually pretty wide and given the build of the plant no reason to thing they would be outside of those.

As far as green is concerned, never really bought into it not yet anyway, the western market is far too immature to pay a premium for green (example being sigmas coined Quintuple Zero Green Lithium which sells at a discount to Aus spod).

As far as costs go, pretty simple, lower grade final product = higher plant yield, more lithia units over the same fixed cost base (higher for UG mines) = lower opex per unit sold = higher margin per tonne of product.

The cost piece linked to product spec is what they will fine tune during rampup, likely why they have been mute on guiding costs. When they figure out what makes most sense for the business and its shareholders by extension, they will announce.

Aimo