Why is the rate for path weeder so different? Watering can 200ml to 8/9l, 200 to 1l for sprayer?

Thank you for contacting Yates. 

When the Yates Pathweeder product is used as directed, the application rates of each active constituent, along with the important non-active constituents, will be equivalent for the concentrate and ready to use (RTU) products. Therefore, the watering can, pressure sprayer and trigger spray rates listed in the Yates Pathweeder Concentrate product label, will each deliver the same amount of active constituents per 15m2.