Thanks... Thought it was something like this...
So wouldn't it make more sense to display a more "vague" but applicable message instead of a somewhat misleading "specific value" of "1"? eg:-
The linked thread is wrong.
A demand of 1 does indeed mean 1t - you can verify this trivially by finding somewhere with a demand of >1 and selling it 1t barrels one at a time, and watching the demand decrease by 1 each time as you do this.
The key is that a demand of 0 does not mean "will not buy", it means "will buy only at minimum price". (A supply of 0 does mean "will not sell", of course).
However, goods pricing does not necessarily work how you might expect.
- price does vary depending on whether the demand is "full" [1] or "empty", but it doesn't vary very *much*. Maybe +/- 10% for most goods. (There's a slightly larger effect on prices for suppliers, but it's still not that big)
- price also varies based on BGS state. The highest I saw in 3.2 was over +500% (though the base price of the good was pretty low). Now in 3.3, the BGS state multipliers themselves get multiplied together. This overwhelms any demand-based price changes, even for the smaller effects.
So there's not really any significant disadvantage to selling at demand zero.
EDIT: I assume this is how it is so that if you want to switch ships you can at least get rid of the cargo you have on board for something, even if the station doesn't technically require it.
[1] Which might be 1t or it might be 100000t depending on the good, the station, and other factors.