Information on the package may be better

Stands on one side of the package, one should apply 1 liter per 10 to 15 m² surface to be treated.

For the preparation of a working solution following stands on the other side of the package: product can be applied verdünt unverdünt or a maximum of 20 parts of water.

My understanding is that the range of diluted depending on dilution with water and, depending on the treatment density between 20 m² (2 liters of undiluted product with 1 liter / 10 m²) and a maximum of 630 m² (2 liters of product + 40 liters of water (= 1:20 ) is 1 liter / 15 m²). Or am I doing a flaw?