Hi Clapek,
Thanks for taking the time to leave such detailed feedback, it's really appreciated.
I've had another look into the pricing issue, and I think you've helped narrow down where the problem is. It looks like some parts of the Prices menu are still using the game's original values rather than BFU's converted ones, which would explain why some products are still showing per 1,000 litres. I'll get that investigated.
As for the trailer shop, another player has also pointed out that I may have overcomplicated things a little. UK trailers are generally advertised by their cubic capacity, so I'm going to revisit that for the next update.
Thanks again for the feedback and for the kind words. It really helps improve the mod.