The article doesn’t even talk about the financial or eco consequences of using too much detergent. In general, a standard dose is half a cap, so if you are filling your cap to the top, you are halving the amount of washes you are getting from the bottle. If you start to measure, and use half the manufacturers’ recommended dose, you will be making your bottle last FOUR times as long, a huge financial saving. On top of this, you will be minimising your eco footprint, due to a quarter of the packaging and consumable resources being used compared with using the full cap.
As the article stated, the lines on the caps do not make measuring easy. I like to take a black Sharpie and draw in the line for a regular load to make my life easier. So make the change, and start measuring. Your wallet, your machine and the planet will thank you!