I have never used this, but it seems to be a white wormer (fenbendazole) which needs to be given at at LEAST TWICE the sheep dose, or 7.5 to 10mg/kg bodyweight. It is a drench?
Now white wormers are NOT very effective anymore, as there is a lot of resistance out there to them, but they are usually licensed for goats.
Have these goats been shown to have worms by FEC?
If you also have sheep you would be better off using Zolvix (no resistance yet), but I do not know the goat dose for those. If you do not have sheep (and therefore cannot buy the wormer in the Agri merchants - and don't tell them it's for goats btw), then your vet can give you Zolvix under the cascade system.
I have used injectable Ivermectin in the past at twice the sheep dose.
Sorry this probably doesn't answer your question really.