Dosing device sheer agony

I bought this product to combat Shield lice on a Ficus benjamina (80L pot).
The amount should be just enough. 5mL / 1L substrate - Giesanwendung.
Dosage:
The attached Dosierball is an absolute impertinence.
If you want to use the whole bottle you have to> 20x fill the ball, by turning an inner plug (done via secondary cap) empty it again. This one comes with a high probability the pesticide in contact. In the end I'm gone over the Dosierball - not removable - saw off! The pesticide is a whitish liquid of medium viscosity, which is not completely soluble in water.
Effect:
Compared to Ceraflor Calypso seems to be less effective against scale insects.