I recently discovered detergents and powders regularly overstate how much is required for a wash, and it even leads to worse results, I'm normally sceptical (or just ignorant) of such articles but I halved how much I used and it seemed to be pretty much true for day to day washing (Don't know about massively dirty clothes, but talking weekly wash here)
I learned this a long time ago when talking with some of my appliance repair friends. Lots of washers break because they're gummed up with excess soap.
I've been running my loads at 1/4 or less of the soap recommended by the manufacturer for years and years and I've never had any issues out of my washer, mechanical or clean wise. Once or twice a year, something will need a second wash or spot treatment, but otherwise everything is pristine.
Not to defend the recommendation as they clearly have an interest in trying to get people to use as much as possible, there is a potentially valid reason for this, which is that it depends on the type of water you have.
Water from a municipal supply is generally well-treated and usually soft, in which case you can get by using less detergent. However with hard water (often sourced from wells), more detergent is needed to get the same cleaning effect.
Maybe they could try to explain this, or maybe they just ignore it for the sake of simplicity (of the instructions on the bottle), and the increased sales is just a nice side effect.
https://www.nytimes.com/wirecutter/blog/stop-using-so-much-l...