Yeah, but if it measures every 1 gram at 0.98 gram, it will display less in the end

Yeah, you “set” it when you filled it. Then it knows the rotations to look for. And if it is off by a lot, it warns you.

Yeah, but this is the system based on the rotations per meters. Which sucks as it’s not that accurate and only warns you when it’s already very low on air pressure.

The accurate one’s are veeeery expensive.

Yeah, but for short trips this doesn’t apply. E.g. I might drive 30 minutes for a 10 minute stay/task.

I don’t know the full details, but part of it:

• In the store you can walk between the books. This takes loads of room. In the Amazon warehouse, this can be veeery cramped.
• The land value of the store is probably mich higher than the Amazon warehouse land.
• They sell much more, so all costs can be shared across a million orders, instead of across just 10 books sold.